STS-65 PRESS KIT
IML-2
JULY 1994
PUBLIC AFFAIRS CONTACTS
For Information on the Space Shuttle
Ed Campion Policy/Management 202/358-1778
Headquarters, Wash., D.C.
James Hartsfield Mission Operations 713/483-5111
Johnson Space Center, Astronauts
Houston
Bruce Buckingham Launch Processing 407/867-2468
Kennedy Space Center, Fl KSC Landing Information
June Malone External Tank/SRBs/SSMEs 205/544-0034
Marshall Space Flight
Center, Huntsville, Ala.
Don Haley DFRC Landing Information 805/258-3448
Dryden Flight Research Center,
Edwards, Calif.
For Information on NASA-Sponsored STS-65 Experiments
Mike Braukus IML-2 Payloads 202/358-1979
Headquarters, Wash., D.C.
Debra Rahn International Cooperation 202/358-1639
Headquarters, Wash., D.C.
Charles Redmond CPCG 202/358-1757
Headquarters, Wash., D.C.
Terri Sindelar SAREX-II 202/358-1977
Headquarters, Wash., D.C.
For Information on DOD-Sponsored STS-65 Experiments
Dave Hess AMOS, MAST 713/483-3498
Johnson Space Center, Houston
CONTENTS
GENERAL BACKGROUND
General Release 3
Media Services Information 5
Quick-Look Facts 6
Shuttle Abort Modes 8
Summary Timeline 9
Payload and Vehicle Weights 10
Orbital Events Summary 10
Crew Responsibilities 11
CARGO BAY PAYLOADS & ACTIVITIES
International Microgravity Laboratory-2 (IML-2) 13
Orbital Acceleration Research Experiment (OARE) 95
IN-CABIN PAYLOADS
Commercial Protein Crystal Growth (CPCG) 96
Air Force Maui Optical Site (AMOS) 97
Military Applications of Ship Tracks (MAST) 97
Shuttle Amatuer Radio EXperiment. 98
STS-65 CREW BIOGRAPHIES
Robert D. Cabana (Commander) 100
James Donald Halsell (Pilot) 100
Richard J. Hieb (Mission Specialist-1) 101
Carl E. Walz (Mission Specialist-2) 101
Leroy Chiao (Mission Specialist-3) 101
Donald A. Thomas (Mission Specialist-4) 102
Chiaki Naito-Mukai (Payload Specialist-1) 102
SPACE SHUTTLE PROGRAM INFORMATION
Statistical Study of Space Shuttle Productivity 104
IML-2 Module Rack 106
Previous Space Shuttle Missions 107
Release: 94-96
INTERNATIONAL MICROGRAVITY LABORATORY MAKES SECOND
FLIGHT
Shuttle Mission STS-65 will see Space Shuttle
Columbia and her seven-person crew conduct the second flight of
the International Microgravity Laboratory-2 (IML-2), a payload
that involves a world-wide research effort into the behavior of
materials and life in the weightless environment of Earth-
orbit.
The STS-65 crew will use furnaces and other
facilities to produce a variety of material structures, from
crystals to metal alloys. From the experiments conducted,
scientists will be able to examine subtle forces which affect
material development in microgravity. Investigators also will
be able to study fluid processes that are masked or distorted
on Earth. This knowledge may help us develop the next
generation of materials needed for high-tech applications and
lead to refinement of materials such as semiconductors,
superconductors, and exotic ceramics and glasses.
The life science experiments conducted during IML-2
will help reveal the role of gravity in shaping life as we know
it and show us how living organisms react and adapt to
microgravity. The reduced gravity encountered in space allows
certain characteristics of cells and organisms to be studied
using innovative laboratory hardware and techniques. Insights
scientists gain about life in space can increase knowledge of
the factors which govern life and health on Earth.
Scientists from NASA, the European Space Agency
(ESA), the French Space Agency (CNES), the German Space Agency
(DARA), the Canadian Space Agency (CSA) and the National Space
Development Agency of Japan (NASDA) have cooperated in planning
experiments which will be performed during the STS-65 mission.
More than 200 scientists developed over 80 investigations for
the IML-2 mission.
Leading the STS-65 crew will be Mission Commander
Robert D. Cabana who will be making his third flight. Pilot
for the mission is James Donald Halsell, Jr. who is making his
first flight. The four mission specialists aboard Columbia are
Richard J. Hieb, the STS-65 Payload Commander, who will be
making his third flight; Carl E. Walz who will be making his
second flight; Leroy Chiao, who will be making his first
flight; and Donald A. Thomas who will be making his first
flight. Chiaki Naito-Mukai from the National Space Development
Agency of Japan will serve as a payload specialist for the STS-
65 mission and will be making her first flight.
-more-
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Launch of Columbia currently is scheduled for no
earlier than July 8, 1994, at 1:11 p.m. EDT. The planned
mission duration is 13 days, 17 hours, 56 minutes. An on-time
launch on July 8 would produce a landing at 7:07 a.m. EDT on
July 22, 1994, at the Kennedy Space Center's Shuttle Landing
Facility.
The Commercial Protein Crystal Growth payload,
sponsored by the Office of Advanced Concepts and Technology
(OACT), will be making its fifth flight on STS-65, using the
Commercial Refrigerator/Incubator Module (CRIM) in the Shuttle
middeck. This complement of experiments contains 60 different
samples focusing on six proteins in various formulations to
enhance the probabilities for successful results.
Two Department of Defense-sponsored experiments will
be flown during the STS-65 mission. The Air Force Maui Optical
System (AMOS) is an electrical-optical facility on the Hawaiian
island of Maui. The AMOS facility tracks the orbiter as it
flies over the area and records signatures from thruster
firings, water dumps or the phenomena of "shuttle glow." The
information obtained by AMOS is used to calibrate the infrared
and optical sensors at the facility. The Military Applications
of Ship Tracks (MAST) experiment on STS-65 is part of a five-
year research program to examine the effects of ships on the
marine environment. The objective of MAST is to determine how
pollutants generated by ships modify the reflective properties
of clouds. MAST will help in understanding the effects of man-
made aerosols on clouds and the resulting impact on the climate
system.
The STS-65 crew will take on the role of teacher as
they educate students in the United States and other countries
about STS-65 mission objectives. Using the Shuttle Amateur
Radio Experiment-II (SAREX-II), astronauts aboard Columbia will
discuss with students what it is like to live and work in
space.
STS-65 will be the 17th flight of Space Shuttle
Columbia and the 63rd flight of the Space Shuttle system.
- end -
MEDIA SERVICES INFORMATION
NASA Television Transmission
NASA television is now available through a new
satellite system. NASA programming can now be accessed on
Spacenet-2, Transponder 5, located at 69 degrees west
longitude; frequency 3880.0 MHz, audio 6.8 MHz.
The schedule for television transmissions from the
orbiter and for mission briefings will be available during the
mission at Kennedy Space Center, Fla; Marshall Space Flight
Center, Huntsville, Ala.; Dryden Flight Research Center,
Edwards, Calif.; Johnson Space Center, Houston and NASA
Headquarters, Washington, D.C. The television schedule will be
updated to reflect changes dictated by mission operations.
Television schedules also may be obtained by calling
COMSTOR 713/483-5817. COMSTOR is a computer data base service
requiring the use of a telephone modem. A voice update of the
television schedule is provided daily at noon EDT.
Status Reports
Status reports on countdown and mission progress, on-
orbit activities and landing operations will be produced by the
appropriate NASA newscenter.
Briefings
A mission press briefing schedule will be issued
prior to launch. During the mission, status briefings by a
Flight Director or Mission Operations representative, and when
appropriate, representatives from the payload team, will occur
at least once per day. The updated NASA television schedule
will indicate when mission briefings are planned.
STS-65 Quick Look
Launch Date/Site: July 8, 1994/Kennedy Space Center - Pad 39A
Launch Time: 1:11 p.m. EDT
Orbiter: Columbia (OV-102) - 17th Flight
Orbit/Inclination: 160 nautical miles/28.45 degrees
Mission Duration: 13 days, 17 hours, 56 minutes
Landing TIme/Date: 7:07 a.m. EDT July 22, 1994
Primary Landing Site: Kennedy Space Center, Fla.
Abort Landing Sites: Return to Launch Site - KSC, Fla.
TransAtlantic Abort Landing - Banjul, The Gambia;
Ben Guerir, Morocco; and Moron, Spain
Abort Once Around - Edwards Air Force Base, Calif.
STS-65 Crew: Robert Cabana, Commander (CDR)
Jim Halsell, Pilot (PLT)
Rick Hieb, Payload Commander (MS1)
Carl Walz, Mission Specialist 2 (MS2)
Leroy Chiao, Mission Specialist 3 (MS3)
Don Thomas, Mission Specialist 4 (MS4)
Chiaki Mukai, Payload Specialist 1 (PS1)
Red shift: Cabana, Halsell, Hieb, Mukai
Blue shift: Chiao, Thomas, Walz
Cargo Bay Payloads: International Microgravity Lab-2 (IML-2)
Middeck Payloads: Commercial Protein Crystal Growth (CPCG)
Shuttle Amateur Radio Experiment-II (SAREX-II)
Orbiter Acceleration Research Experiment (OARE)
Military Applications of Ship Tracks (MAST)
Other: Air Force Maui Optical Site (AMOS)
Detailed Test Objectives/Detailed Supplementary Objectives:
DTO 251: Entry Aerodynamic Control Surfaces Test
DTO 301D: Ascent Structural Capability Evaluation
DTO 307D: Entry Structural Capability Evaluation
DTO 312: External Tank Thermal Protection System
Performance
DTO 319D: Orbiter/Payload Acceleration and Acoustics
Environment Data
DTO 414: Auxiliary Power Unit Shutdown Test
DTO 623: Cabin Air Monitoring
DTO 655: Foot Restraint Evaluation
DTO 663: Acoustic Noise Dosimeter Data
DTO 665: Acoustic Noise Sound Level Data
DTO 667: Portable In-Flight Landing Operations
Trainer
DTO 674: Thermo-Electric Liquid Cooling System
Evaluation
DTO 805: Crosswind Landing Performance
Detailed Test Objectives/Detailed Supplementary Objectives
(cont'd)
DTO 913: Microgravity Measurement Device
DSO 314: Acceleration Data Collection
DSO 326: Window Impact Observations
DSO 484: Assessment of Circadian Shifting in
Astronauts by Bright Light
DSO 485: Inter Mars TEPC
DSO 487: Immunological Assessment of Crewmembers
DSO 491: Characterization of Microbial Transfer Among
Crewmembers
During Space Flight
DSO 603B: Orthostatic Function During Entry, Landing
and Egress
DSO 604: Visual-Vestibular Integration as a Function
of Adaptation
DSO 605: Postural Equilibrium Control During
Landing/Egress
DSO 608: Effects of Space Flight on Aerobic and
Anaerobic Metabolism
During Exercise
DSO 610: In-Flight Assessment of Renal Stone Risk
DSO 614: The Effect of Prolonged Space Flight on Head
and Gaze
Stability During
Locomotion
DSO 621: In-Flight Use of Florinef to Improve
Orthostatic Intolerance
Postflight
DSO 626: Cardiovascular and Cerebrovascular Responses
to Standing Before
and After Space Flight
DSO 901: Documentary Television
DSO 902: Documentary Motion Picture Photography
DSO 903: Documentary Still Photography
SPACE SHUTTLE ABORT MODES
Space Shuttle launch abort philosophy aims toward
safe and intact recovery of the flight crew, Orbiter and its
payload. Abort modes include:
* Abort-To-Orbit (ATO) -- Partial loss of main engine
thrust late enough to permit reaching a minimal 105-nautical
mile orbit with orbital maneuvering system engines.
* Abort-Once-Around (AOA) -- Earlier main engine
shutdown with the capability to allow one orbit around before
landing at Edwards Air Force Base, Calif.
* TransAtlantic Abort Landing (TAL) -- Loss of one or
more main engines midway through powered flight would force a
landing at either Banjul, The Gambia; Ben Guerir, Morocco; or
Moron, Spain.
* Return-To-Launch-Site (RTLS) -- Early shutdown of
one or more engines, and without enough energy to reach Banjul,
would result in a pitch around and thrust back toward KSC until
within gliding distance of the Shuttle Landing Facility.
STS-65 contingency landing sites are the Kennedy
Space Center, Edwards Air Force Base, Banjul, Ben
Guerir and Moron.
STS-65 Summary Timeline
Flight Day One
Ascent
OMS-2 burn (163 n.m. x 160 n.m.)
IML-2 activation/operations
Blue Flight Days Two-Thirteen
IML-2 operations
Red Flight Days Two-Thirteen
IML-2 operations
Blue Flight Day Fourteen
IML-2 operations
Red Flight Day Fourteen
Flight Control Systems Checkout
Lower Body Negative Pressure Device
Blue/Red Flight Day Fifteen
Cabin stow
Payload deactivation
IML-2 deactivation
Deorbit
Entry
Landing
STS-65 VEHICLE AND PAYLOAD WEIGHTS
Vehicle/Payload
Pounds
Orbiter (Columbia) empty and 3 SSMEs 181,443
International Microgravity Lab-2 21,187
Commercial Protein Crystal Growth 58
Orbiter Acceleration Research Experiment 249
Shuttle Amateur Radio Experiment-II 37
Military Applications of Ship Tracks 66
Detailed Supplementary/Test Objectives 205
Total Vehicle at SRB Ignition 4,522,321
Orbiter Landing Weight 228,640
STS-65 ORBITAL EVENTS SUMMARY
EVENT START TIME VELOCITY CHANGE
ORBIT
(dd/hh:mm:ss)
(feet per second) (n.m.)
OMS-2 00/00:42:00 221
fps 163 x 160
Deorbit 13/16:56:00 270
fps N/A
Touchdown 13/17:56:00 N/A
N/A
STS-65 CREW RESPONSIBILITIES
TASK/PAYLOAD PRIMARY
BACKUPS/OTHERS
IML-2 Hieb
Middeck Payloads:
SAREX Cabana
Thomas
CPCG Cabana
Walz
MAST Walz
Cabana
OARE Thomas
Walz, Halsell
Detailed Test Objectives:
DTO 312 Thomas
Chiao
DTO 414 Halsell
Walz
DTO 623 Walz
Halsell
DTO 655 Chiao
Hieb
DTO 663 Cabana
Walz
DTO 665 Cabana
Walz
DTO 667 Cabana
Halsell
DTO 805 Cabana
Halsell
Detailed Supplementary Objectives:
DSO 314 Halsell
Walz
DSO 485 Cabana
Walz
Other:
Photography/TV Halsell
Walz
In-Flight Maintenance Walz
Halsell
EVA Chiao
(EV1) Thomas (EV2), Walz (IV)
Earth Observations Halsell
Cabana
Medical Cabana
Walz
IML -2 PAYLOADS: CREW ASSIGNMENTS
PAYLOAD PRIMARY
BACKUPS/OTHERS
AAEU Thomas
Mukai, Chiao, Hieb
APCF Chiao
Hieb, Thomas, Mukai
BDPU Thomas
Mukai, Chiao, Hieb
Biorack Chiao
Hieb, Thomas, Mukai
CPF Chiao
Hieb, Thomas, Mukai, Cabana
EDOMP Mukai
Hieb, Thomas, Chiao
FFEU Mukai
Thomas, Hieb, Chiao
LIF Mukai
Thomas, Hieb, Chiao
NIZEMI Chiao
Hieb, Thomas, Mukai
PAWS Cabana
Halsell, Walz
QSAM Thomas
Mukai, Chiao, Hieb
RAMSES Thomas
Mukai, Chiao, Hieb
RRMD Mukai
Thomas, Hieb, Chiao
SAMS Thomas
Mukai, Chiao, Hieb
SCM Hieb
Mukai
TEI/CCK Mukai
Thomas, Hieb, Chiao
TEMPUS Thomas
Mukai, Chiao, Hieb
IML-2: THE SECOND INTERNATIONAL MICROGRAVITY LABORATORY
The second International Microgravity Laboratory
Spacelab mission brings together scientists from around the
world in a search for answers which might only be found in the
unique laboratory of space.
As the Shuttle orbits Earth, it provides a nearly
weightless, or microgravity, environment. Microgravity cannot
be duplicated for longer than a few seconds with Earth-based
facilities. The IML-2 mission objective is to conduct
microgravity and life sciences research that can only be
accomplished in this low-gravity environment.
In a space laboratory, some of the physical processes
which affect experiments on Earth are not as dominant.
Gravity-related disturbances such as buoyancy, sedimentation
and hydrostatic pressure cannot only limit the quality of some
materials but also limit the ways materials can be studied.
IML-2 scientists will use furnaces and other
facilities to produce a variety of material structures, from
crystals to metal alloys. They will examine subtle forces
which affect material development in microgravity. Scientists
also will be able to study fluid processes that are masked or
distorted on Earth. Nearly every physical science depends on
an understanding of these basic mechanisms. This knowledge may
help us develop the next generation of materials needed for
high-tech applications and lead to refinement of materials such
as semiconductors, superconductors, and exotic ceramics and
glasses.
Life science research on IML-2 will help reveal the
role of gravity in shaping life as we know it and show us how
living organisms react and adapt to microgravity. Before we
can make space our second home, we must understand how living
things are affected by reduced gravity and radiation in the
space environment. Insights scientists gain about life in
space can increase knowledge of the factors which govern life
and health on Earth.
For instance, previous space flights have
demonstrated that high quality protein crystals, suitable for
X-ray analysis, can be grown in space. If the structures of
certain proteins can be determined by examining these crystals,
not only will we learn about an essential component of all life
forms, but we could use this knowledge to improve the medical
treatment of many diseases.
IML-2 Science
More than 200 scientists from six space agencies
developed over 80 investigations for the IML-2 mission.
Representatives of the European Space Agency (ESA), the French
Space Agency (CNES), the German Space Agency (DARA), the
Canadian Space Agency (CSA) and the National Space Development
Agency of Japan (NASDA) are joining NASA in this mission of
discovery.
An international crew will conduct these experiments
inside Spacelab, a versatile research laboratory which fits in
the Space Shuttle cargo bay. It is an appropriate place for
multi-national research, since Spacelab was developed by the
ESA in the late 1970s and early 1980s as its contribution to
the American Space Shuttle Program. IML-2 uses the pressurized
Spacelab module. With its extra work area, power supplies,
data management capability and versatile equipment racks,
scientists in space can work much as they would in their
laboratories on Earth.
Many IML-2 experiments owe their heritage to earlier
Skylab, sounding rocket and ground-based experiments. Some
have evolved over several Spacelab missions. Facilities flown
on previous flights are being flown again to probe new
scientific questions or to expand on prior studies. This
mission also will introduce some new experiment facilities,
designed to give scientists additional tools for finding
answers in the microgravity of space.
MATERIALS SCIENCE: NASDA's Large Isothermal Furnace melts and
uniformly mixes compounds, then cools them to produce a solid
sample. The Electromagnetic Containerless Processing Facility
from Germany positions metal alloys so they do not touch
container walls and melts them in an ultra-pure environment.
The facility records information on the alloys as they
solidify.
FLUID SCIENCE: The European Space Agency's Bubble, Drop and
Particle Unit contains special optical diagnostics, cameras and
sensors for studying fluid behavior in microgravity. Their
Critical Point Facility, which flew on IML-1, investigates
fluids as they undergo critical phase transitions from liquids
to gases.
MICROGRAVITY ENVIRONMENT AND COUNTERMEASURE: NASA's
Space
Acceleration Measurement System, on its tenth flight, will be
joined on IML-2 by the German Space Agency's Quasi-Steady
Acceleration Measurement experiment. Together, they will give
scientists the most complete picture yet of the subtle motions
which can disturb sensitive microgravity experiments. Japan's
Vibration Isolation Box Experiment System will test a special
material designed to reduce the effect of those accelerations.
BIOPROCESSING: ESA's Advanced Protein Crystallization Facility
will provide a versatile environment for growing a variety of
protein crystals using three different techniques. A video
recording device will allow scientists to study the crystal
growth process after the mission. Two experiment facilities,
Applied Research on Separation Methods Using Space
Electrophoresis from France and the Free Flow Electrophoresis
Unit from Japan, will use electric fields to separate
biological materials into their individual components. The
process is widely used on Earth to produce ultra-pure products
for pharmaceutical drugs.
SPACE BIOLOGY: Two space biology facilities from the 1992
Japanese Spacelab-J mission will fly on IML-2. Scientists will
study the spawning, fertilization, embryology and behavior of
newts and fish housed in the Aquatic Animal Experiment Unit.
The Thermoelectric Incubator/Cell Culture Kit will accommodate
the study of plant and animal cells. IML-2 will be the third
flight for the European Space Agency's Biorack, which supports
investigations into the effects of microgravity and cosmic
radiation on cells, tissues, plants, bacteria, small animals
and other biological samples. The Slow Rotating Centrifuge
Microscope from Germany contains equipment for observing the
movement and behavior of one-celled and multi-cellular
organisms at various gravity levels. Materials scientists will
take advantage of its capabilities to observe the
solidification of a transparent model alloy as well.
HUMAN PHYSIOLOGY: Canada's Spinal Changes in Microgravity
experiment, an expanded version of an IML-1 investigation, will
use stereophotographs and special ultrasound and monitoring
equipment to record changes in crew members' spinal and
neurosensory systems. NASA's Extended Duration Orbiter Medical
Project will continue investigations designed to maintain and
evaluate crew health and safety on long-duration Shuttle
flights. The crew will use the Performance Assessment
Workstation, a laptop computer, to help determine their mental
ability to perform operational tasks during long-duration
missions.
RADIATION BIOLOGY: Germany's Biostack, a veteran of three
Spacelab missions, sandwiches biological specimens between
radiation detectors in a sealed container to determine how
cosmic radiation affects them. Japan's Real-Time Radiation
Monitoring Device will test methods which may be used for space
radiation forecasting aboard future spacecraft.
Mission Operations
The Marshall Space Flight Center in Huntsville, Ala.,
manages IML-2 for NASA's Office of Life and Microgravity
Science and Applications, Washington, D.C. Experiment
operations for the 14-day flight will be directed from the
agency's Spacelab Mission Operations Control facility at
Marshall.
During the mission, hundreds of scientists and
engineers representing the many IML-2 experiments will work in
the Science Operations Area. From there, they can monitor
experiments via video and voice links with the Shuttle, send
remote commands to their instruments, discuss operations with
the crew in space, and coordinate mission activities with their
colleagues from other experiment teams. The ESA experiment
teams will be backed up by colleagues working at remote sites
in Amsterdam, The Netherlands; Brussels, Belgium; Naples,
Italy; Toulouse, France; and Cologne, Germany. Additional
science teams will be located at the Johnson Space Center and
the Kennedy Space Center.
Primary responsibility for operating the experiments
in orbit belongs to the Spacelab science crew. Payload
Commander Rick Hieb, Mission Specialists Leroy Chiao and Don
Thomas, and Payload Specialist Chiaki Mukai will work in two
12-hour shifts. Operating the Spacelab 24 hours a day enables
scientists to get the most from valuable time in orbit. The
crew will work from a preplanned master timeline, with
adjustments made for unexpected opportunities.
After landing, many experiment samples, some of which
have limited lifetimes, will be returned to the scientists for
evaluation. Later, experiment hardware will be returned to the
space agency that developed it. Computer tapes, voice
recordings, video tapes and other data will be organized and
forwarded to investigators. Analysis of the results will start
even before the Shuttle touches down and may continue for
several years.
The investigators will be rewarded with new insights
into the intrinsic properties of materials, increased knowledge
about how gravity affects living systems on Earth, and no doubt
new questions to be answered in the unique laboratory of space.
Large Isothermal Furnace
Payload Developer: NASDA
Objective: The Large Isothermal Furnace uniformly heats large
materials samples in a vacuum, then cools them rapidly to
determine the relationships between the structure, processing
and properties of materials. On IML-2, scientists will
solidify five samples under various temperature conditions,
studying ceramic/metallic composites, semiconductor alloys, and
liquid phase sintering. Sintering is a process for combining
dissimilar metals, using heat and pressure to join them without
reaching the melting point of one or both metals.
Significance: Knowledge gained from post-flight sample
analysis will help scientists better understand and improve
production techniques on Earth. They also will use the results
to assess the feasibility of producing unique materials in
space.
Science: In order to create lighter, stronger or more
temperature-resistant materials, metallurgists often combine
two or more different metals into an alloy which has more
desirable qualities than each of its ingredients. Or they may
combine dissimilar substances such as metals and ceramics to
produce structural materials that are stronger and lighter than
conventional metals.
The key to success is the uniform distribution of the
various chemical components throughout the finished product.
On Earth, gravity causes ingredients with dissimilar densities
to settle differently as heavier components are pulled
downward. This gravity-induced movement, called sedimentation,
causes uneven particle distribution throughout the material.
It can diminish the uniformity of its microscopic structure,
distort the finished product's shape, and decrease the
precision of the casting process.
A microgravity environment greatly reduces buoyancy-
driven convection and sedimentation. This may allow the
uniform mixture of dissimilar materials in spite of great
density differences.
Experiment Hardware and Operations: The facility is a
resistance-heated vacuum furnace designed to uniformly heat
large samples. It has a maximum operating temperature of about
2,900 degrees Fahrenheit (1,600 !C) and can rapidly cool a
sample by admitting helium gas into the heating chamber.
The furnace consists of a sample container and
heating element, surrounded by a vacuum chamber. A crew member
inserts a sample cartridge through an access port in the front
of the facility. A screw-type connector secures the sample in
the furnace. Air within the chamber is evacuated through the
Spacelab vent system.
The furnace control equipment runs through a pre-
programmed heating/cooling cycle to process the sample, and
data from temperature sensors are recorded. A gas-driven
piston within the sample cartridge can be used to apply
pressure to the sample during the experiment.
At the end of the experiment, helium gas is injected
into the furnace to allow rapid cooling of the sample. The
cartridge is then removed and another can be installed to start
a new experiment. Sample cartridges are returned to Earth for
analysis.
Background: The Large Isothermal Furnace was developed by the
National Space Development Agency of Japan (NASDA). It flew on
the Spacelab-J mission in September 1992. Eight samples were
processed successfully during that flight and are being
analyzed by investigators.
Gravitational Role in Liquid Phase Sintering
Experiment Facility: Large Isothermal Furnace
Principal Investigator:
Dr. Randall M. German
Pennsylvania State University
University Park, Pa.
Objective: This experiment will determine how gravity changes
heavy alloys of tungsten, nickel and iron during sintering, a
process for combining dissimilar metals. Sintering uses heat
and pressure to join powdered forms of different metals without
both components.
The material will be heated so the iron and nickel
form a liquid, surrounding the uniformly dispersed powdered
tungsten. Samples will be analyzed post-flight to investigate
both macrostructural changes, such as those in shape and
texture, and microstructural changes, including density and
high-temperature strength.
Significance: Liquid phase sintering is a process used to
produce alloys of novel compositions. For example, due to
density differences between the tungsten and the iron-nickel
liquid that forms at high temperatures, sintering is the only
process by which this alloy can be fabricated. This IML-2
investigation will add to ground-based research, which
indicates that gravity plays a role in distorting the
microstructure of samples sintered on Earth. Tungsten heavy
alloys were chosen for this experiment because of widespread
interest in the alloy system, extensive sintering experience on
Earth, a large database on properties, and approximately a
factor of two density difference between the liquid and solid
phases.
Background: Five different compositions of tungsten-nickel
alloy were sintered at 2,730 degrees Fahrenheit (1,500 degrees
C) in the Large Isothermal Furnace during the Spacelab-J
mission. One sample set was sintered for 60 minutes, and
another was sintered for 300 minutes. Samples with larger
percentages of nickel tended to behave like liquids. Since
they were not distorted by gravity as they would have been on
Earth, they solidified into spherical shapes. Scientists
concluded that the mixture of liquid and small solid particles
behaves like liquid in microgravity, regardless of density
differences in the materials, when a continuous liquid layer is
formed at the surface.
Operations: A crew member will load a sample cartridge
containing seven different compositions of tungsten heavy alloy
into the Large Isothermal Furnace, then activate a
preprogrammed, computer-controlled processing sequence. The
cartridge will be rapidly heated to 2,730 degrees Fahrenheit
(1,500 degrees C) for a little over an hour, gradually cooled
with water for almost another hour, then rapidly cooled by a
continuous flow of helium for about 3-1/2 hours more. The
astronaut then will remove the cartridge and stow it for return
to Earth.
The procedure will be repeated with two more
cartridges. Sintering time and sample composition will be
varied to identify their effects on final properties of the
composites.
The samples, as well as thermal and acceleration data
collected during the experiment, will be analyzed post-flight.
Mixing of a Melt of Multicomponent Compound Semiconductor
Experiment Facility: Large Isothermal Furnace
Principal Investigator:
Dr. Akira Hirata
Waseda University
Tokyo, Japan
Objective: This investigation will develop a new method for
uniformly mixing melted compound semiconductors. It will test
whether the components can be mixed faster and more uniformly
using Marangoni convection, that is, fluid flows driven by the
concentration differences on the surface of a liquid.
Science: Semiconductors are made of several constituents with
different densities. On Earth, gravity separates the
components, as heavier materials settle from lighter ones. In
space, without any mixing devices, it may be possible to mix
these components more uniformly and faster using Marangoni
convection, a type of fluid flow driven by differences in
surface tension. Although these flows exist on Earth, they are
masked by the much stronger forces of sedimentation and
buoyancy-driven convection, caused by density differences
within the liquid.
Surface tension is the force which causes falling
water to form into drops. In space, away from gravity's
distortion, it forms an uncontained liquid into a perfect
sphere. Previous space experiments have demonstrated that
variations in the temperature on the free surface of a fluid
create predictable flow patterns within that fluid.
Investigators for this experiment will test whether this gentle
flow is a useful tool for uniformly mixing semiconductor
components.
Significance: Semiconductors are materials whose conductivity
is poor at low temperatures, but is improved by application of
heat, light or voltage. They are widely used in computers and
other electronic devices to transmit electrons in a controlled
manner. A better mixture would result in a semiconductor with
more uniform content, allowing it to transmit electrons more
efficiently.
Operations: Two different compounds of indium-gallium-antimony
(InGaSb) will be melted and solidified in the Large Isothermal
Furnace to form semiconductors. The experiment cartridge will
contain a total of six samples.
Four samples will be processed using Marangoni
convection to mix the components. As a material cools and
contracts, a void is left in the sample ampoule. Material next
to the void forms a free surface which does not touch the sides
of the ampoule, allowing Marangoni convection to occur.
Two samples will be processed using only molecular
diffusion to mix the components. The void created by cooling
and contraction, and the resulting free surface will be
eliminated by a gas-driven piston within the cartridge. It
will automatically move forward to take up the empty space as
the sample material contracts.
The solidified crystals will be compared postflight
to determine crystal quality, crystal shape, and size of
crystal particulates. Scientists also will compare the effects
of the two processing methods on mixing of the melted
components and the uniformity of the solidified semiconductor.
Background: Dr. Masami Tatsumi grew an indium-gallium-arsenide
crystal in the Spacelab-J Gradient Heating Furnace. A piston
was used to prevent Marangoni convection within that
experiment. The resulting mixture was more uniform than that
of a comparison crystal grown on Earth, but it was not
completely homogeneous.
Effect of Weightlessness on Microstructure and
Strength of Ordered TiAl Intermetallic Alloys
Experiment Facility: Large Isothermal Furnace
Principal Investigator:
Dr. Masao Takeyama
National Research Institute of Metals
Tokyo, Japan
Objective: This experiment will melt and resolidify a
titanium-aluminum alloy to which ceramic particles of titanium
diboride have been added. The particles should increase the
high-temperature strength of the material, improving the
microstructure and thus the mechanical properties of the alloy.
Science: Ceramic particles must be evenly distributed within
an alloy to improve grain structure and mechanical properties.
On Earth, differences in density between the particles and the
alloy prevent uniform distribution, because gravity pulls the
heavier particles downward. In microgravity, the uneven
distribution caused by density differences should be prevented.
Heat convection, which also affects solidification, should be
minimal.
Significance: Results should help investigators understand
some of the principal influences that occur during this type of
material processing. Insights gained about microstructural
control could be applied to producing more effective materials
on Earth. This technology for controlling alloy microstructure
may be applied to improve high-temperature alloys needed for
high-tech aircraft and spacecraft.
Operations: A crew member will place a cartridge containing
four titanium-aluminum samples, each 18 mm in diameter and 25
mm long, in the Large Isothermal Furnace. Two of the samples
will have ceramic particles added; the others will not. They
will be heated to approximately 2820 degrees Fahrenheit (1550
degrees C), then solidified in microgravity.
This is planned to be the last sample cartridge
processed in the furnace during IML-2, and it will remain in
the facility until after landing. Post flight, scientists will
study the effect of the resulting microstructure on mechanical
properties such as strength. In addition to the two flight
samples being compared with one another, they will be compared
with those processed on the ground.
Electromagnetic Containerless Processing Facility
Tiegelfreies Elektromagnetisches Prozessieren Unter
Schwerelosigkeit
(TEMPUS)
Payload Developer: German Space Agency (DARA)
Objective: To study the solidification of materials from the
liquid state, a subject of immense scientific and practical
interest. Not only are solidification phenomena important to
science, but many industrial processes involve solidification.
On Earth, liquids generally must be held in
containers, which can affect the liquid's properties. For
example, a container determines a liquid's shape, and contact
with the container walls can diminish the purity of the metal
sample.
In microgravity, samples can be processed in a
containerless facility, which avoids contact with any surface.
The Electromagnetic Containerless Processing Facility, known as
TEMPUS, is a levitation melting facility for containerless
processing of metallic samples in an ultraclean microgravity
environment. It was developed by the German Space Agency.
Science: In the absence of a container, most pure molten
metals can be cooled to below their solidification point and
still remain fluid. Crystalline solidification begins when
small, isolated clusters of atoms arrange in a regular,
repeating form. This process is known as nucleation, and the
clusters are called nuclei. Atoms fall into place on these
clusters causing the sites to grow until the entire mass
becomes solid.
Nucleation occurs at solid to liquid boundaries,
such as the boundary between solid container walls and the
liquid sample it holds. The container walls, consisting of
arranged atoms, act as the nuclei site. The resulting solid
will appear as a patchwork of many small crystals as opposed to
fewer, larger crystals produced by fewer nucleation sites in
microgravity. It is this undercooling phenomenon that
scientists are interested in studying.
Background: This is the maiden flight for the TEMPUS facility.
The 22 samples accommodated by the facility are being shared by
many of the principal investigators so as to gather the maximum
scientific data from the limited number of alloy samples
available. Therefore, as a general rule, each sample is of
interest to more than one principal investigator.
Hardware: The TEMPUS system uses an electric current flowing
through coils of copper tubes to produce magnetic fields. By
carefully forming the coils, it is possible to create an area
of minimum field strength in which the sample will levitate or
float.
On Earth, lifting a sample in apparent defiance of
gravity requires a very powerful electromagnetic force. Not
only does this deform the sample and agitate the melted alloy,
but independent temperature control is impossible. In
microgravity, positioning of the sample and temperature control
can be accomplished accurately and precisely because the power
necessary for positioning the sample is greatly reduced. The
reduced amount of current results in diminished fluid motion
which is less intrusive on the phenomena being examined.
The 22 spherical specimens, each up to 0.4 inch (10
millimeters) in diameter, can be accommodated on a storage disk
within the TEMPUS unit. The disk rotates until the desired
specimen is positioned over a transfer mechanism. The
mechanism unlocks the sample holder and transfers the sample to
the processing area within the levitation coils. Processing
can occur in a vacuum, or in an ultra-pure helium/argon
atmosphere. As the sample cools, experimental data are
recorded. Different views of the process are recorded by video
cameras.
The TEMPUS system provides the means for physically
manipulating the sample during processing. Rotations and
oscillations can be controlled through the application of a
direct current magnetic field. Nucleation can be initiated at
any desired undercooled temperature by touching the sample with
a needle driven by the transfer mechanism, causing the entire
sample to rapidly solidify. Also, the sample can be vibrated
by applying short power pulses to the heating or levitation
coils. By observing how the sample reacts to vibration,
properties such as surface tension and viscosity can be
inferred.
Operations: Experiment procedures are almost completely
microprocessor-controlled and require very little crew
interaction other than start up and shut down. The TEMPUS unit
is reprogrammed between each experiment from the ground. The
crew on board, or ground controllers, can modify any
experiment parameters during sample processing.
The team of investigators will study various
thermodynamic and kinetic properties of 22 samples. The
metallic samples have melting points between 1634 and 3362
degrees Fahrenheit (890 and 1850 degrees C) when heated in the
TEMPUS unit.
Effects of Nucleation by Containerless Processing in Low
Gravity
Experiment Facility: TEMPUS
Principal Investigator:
Robert J. Bayuzick
Vanderbilt University
Nashville, Tenn.
Objective: This experiment has a two-fold purpose:
- to better understand specific details of how metals
solidify, and
- to investigate ways in which the solidification
process can be controlled.
An extensive series of experiment runs will be
conducted to provide comparative data for determining the time
and temperature at which a metal begins to turn into a solid.
Scientists hope to pinpoint what phenomenon "kicks-off" the
solidification process. The series will be conducted in the
Electromagnetic Containerless Processing Facility or TEMPUS.
On Earth, the electromagnetic force necessary to
levitate the sample so that it floats in apparent defiance of
gravity, is so powerful that it deforms and agitates the molten
metal sample. Also, levitation techniques in a 1-g environment
result in large liquid flows, or convection currents, within
the sample. In microgravity, the amount of electromagnetic
forces required is reduced, thus causing less disturbance and
stress to the free-floating, spherical sample. This
containerless environment will allow the molten metal to
nucleate and grow a crystal without being influenced by a
container's molecular structure.
Science: Pure liquid metals can remain in a liquid state below
the point at which they should solidify. This process is
called undercooling. In this experiment, scientists will try
to keep the metal in a molten state for as long as possible, at
the lowest possible temperature.
The condition when an undercooled liquid first begins
to solidify is called nucleation. A cluster of atoms acts as a
nucleation site, or foundation, for the crystal to build upon.
Free-moving atoms attach themselves to this site, growing into
a solid crystal structure. Scientists hope to determine the
nucleation properties for the element zirconium, a strong,
ductile metallic element used chiefly in ceramic and refractory
compounds as an alloying agent. The nucleation properties are
what characterize the molten liquid's random movement of atoms
into an ordered pattern as a solid metal. Scientists want to
study this process under the condition of a high degree of
undercooling.
Significance: Solidifying metals is one of the most important
processes in industry. Learning more about the basic
nucleation phenomena may provide clues for making different
materials. The nucleation phenomenon is the most basic process
governing the solidification of metals.
Background: This experiment has been performed on Earth using
drop tubes that simulate low gravity for a few seconds.
However, the precise measurement of temperature is difficult
because during freefall the specimen is moving with respect to
the detectors.
Operations: A spherical sample of zirconium about three-
eighths of an inch (8 to 10 mm) in diameter will be levitated,
heated to 3542 degrees Fahrenheit (1950 degrees Celsius),
melted and then cooled about 300 degrees below the normal
solidification point when nucleation is expected to take place.
The experiment will consist of approximately 100 melting,
cooling, nucleation and solidification cycles. The series
will take place over four hours. Each time the sample is
melted and resolidified, the nucleation temperature and rate of
crystal growth will be recorded for comparison with Earth-based
results to further the understanding of nucleation phenomena.
Non-Equilibrium Solidification of Largely Undercooled Melts
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Dieter M. Herlach
DLR Institute for Space Simulation
Cologne, Germany
Objective: This experiment has a two-fold objective. First,
it will investigate dendritic and eutectic solidification
velocity resulting from undercooling. These measurements can
be used to test and refine dendritic and eutectic
solidification theories. Second, this investigation will study
the nucleation of metastable phases below an alloy's normal
solidification temperature.
Science: Dendrites -- from the Greek word for "tree" -- are
tiny branching structures that form inside molten metal alloys
when they solidify during manufacturing. The size, shape and
structure of the dendrites have a major effect on the strength,
ductility and usefulness of an alloy.
A eutectic substance -- also from a Greek word
("well-melting") -- is a material that has a melting point
lower than that of any of its components. This property makes
it an important material, one whose microstructure has a strong
impact on mechanical, electrical and magnetic properties. An
example of the eutectic phenomenon is putting salt onto ice.
The salt-water mixture lowers the melting point, causing the
ice to melt.
Nucleation is the starting point for solidification.
The tiniest possible crystal, which scientists call an embryo,
sets the solidification process into motion. If the atomic
arrangement within the embryo differs from that in the usual
stable solid, a metastable crystalline phase forms.
The atoms of these metastable crystals have different
structural arrangements that change the alloy's properties,
such as improving mechanical elasticity and strength. Coal is
an example of a material produced at the normal solidification
temperature. It is the stable, solid form of carbon. When the
atomic structure solidifies at specific conditions, a diamond
is created. Diamond is the metastable solid form of carbon.
This means that in thousands of years a diamond will eventually
turn into a piece of coal, the material's more stable form.
When nucleation occurs at other temperatures below the normal
solidification point, other materials can be created. Coal and
diamond are just two of many possibilities, all dependent on
the conditions at which nucleation occurs.
Significance: There are two reasons why these experiments are
performed in microgravity. First, crystal growth can be
strongly affected by convective fluid flow in the molten metal.
The low acceleration environment in space effectively
eliminates convection. Comparing space experiment data with
Earth experiment data is the only practical way to separate the
effects of convection from the underlying mechanism of crystal
growth. On the other hand, the experiment conditions such as
containerless processing of melts in an ultraclean environment
promise a substantial extension of the degree of undercooling
that can be achieved. It is at these very low undercooling
temperatures that scientists hope to observe the nucleation of
various metastable phases.
Operations: Two methods will be used to study these phenomena
in the containerless environment provided within the TEMPUS
facility. First, iron-nickel, nickel-carbon and nickel-silicon
will be heated to 100 degrees above their melting point. Then
they will be allowed to cool as far into the undercooling range
as possible, until nucleation spontaneously occurs, and many
independent, separate dendrites grow. The solidification
velocity will be measured once nucleation occurs.
The second method will use a needle to terminate the
undercooling phase. The needle will provide a nucleation site,
inducing solidification at a specific temperature below the
normal solidification point. Investigators will carefully
control where and when dendrites begin to grow inside the
experiment sample.
Several different time profiles at various
temperatures will be obtained for each sample. The
microstructure of the materials will be analyzed post flight,
along with temperature, pressure and acceleration data.
Alloy Undercooling Experiments
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Merton C. Flemings
Massachusetts Institute of Technology
Cambridge, Mass.
Objective: Atoms in a molten liquid alloy line up in a
specified order as the alloy cools and becomes a solid crystal.
Scientists hope to learn more about the order in which atoms
attach to each other as they grow into a crystal structure.
They also want to study the speed at which the crystallization
process occurs.
Science: Liquid alloys allowed to solidify slowly at their
natural freezing point repeatedly form what is called an
equilibrium atomic structure. Atoms are consistently ordered
in an identical pattern. When the solidification process is
changed, the atomic structure is affected. Molten liquids that
are undercooled below the point where they usually become a
solid crystallize faster than when they solidify at their
normal freezing point. The particles are frozen rapidly right
where they are, in a matter of milliseconds. This quick
cooling creates metastable solid phases that are not considered
"normal" or stable. Scientists hope their results reveal how
the fast-frozen solids are different and if the metal alloy's
characteristics are improved. It is possible the alloy will be
stronger.
The metal's properties are expected to change because
undercooling allows the scientist to "supersaturate" the
nickel-tin alloy. Tin makes up a small percentage of the
initial alloy sample. However, when the alloy is
supersaturated, a higher concentration of the sample is
comprised of tin. This should alter the metal's properties.
Significance: Scientists and engineers will study the
experiment results to determine how the properties of metals
change in an unstable fast-frozen, supersaturated state. This
may help industry make better metals. For example, in the
casting of high-performance metal components like jet engine
turbine blades, each blade is the result of a crystal grown
from a single nucleation site. Improving this process may make
possible turbine blades that would have greater operating
efficiency if the blades can be constructed of a metal capable
of withstanding higher temperatures.
Operations: Three alloy samples will be levitated, melted and
solidified in the Electromagnetic Containerless Processing
Facility, nicknamed TEMPUS. Two nickel-tin spheres, one
containing 25 percent tin and one almost one-third tin, will be
tested and a third sample, of pure nickel, will be processed
for a control experiment.
Structure and Solidification of Largely Undercooled Melts of
Quasicrystal-Forming Alloys
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Knut Urban
Institute for Solid State Physics Research Center Julich
Julich, Germany
Objective: This experiment studies a unique feature of some
metallic alloys - the presence of structural elements based on
atom arrangements with 20 triangular sides, a shape called
icosahedral. These multi-sided structures are a fairly recent
discovery known as quasicrystals.
Science: Quasicrystals are so small they are called nano-
crystals. Scientists are not even sure they can be considered
true crystals. Because they are multi-sided -- having the
icosahedral shape -- they are unstable building blocks.
Therefore, they are distributed in small pockets throughout
some metal alloys. As an analogy, children's building blocks -
- squares, triangles and rectangles -- fit together in
repetitive patterns forming a sturdy, solid structure.
However, icosahedral shapes cannot tightly fit together,
leaving empty spaces that weaken a building arrangement such as
a crystal structure.
This investigation also is interested in the
undercooling phenomena of these quasicrystals. Using the
TEMPUS facility, metallic alloys can be cooled well below their
melting temperature without solidification.
The quasicrystalline state in metallic alloys was
discovered in 1984 as the third state of solid matter. The
other two are normal crystalline and glassy states.
Quasicrystals exhibit excellent structural order based on atom
arrangements that do not permit long-range periodicity. This
feature provides quasicrystalline materials with a high degree
of hardness and novel electrical and physical properties.
Small pockets of quasicrystals are located throughout the
alloy.
Significance: This experiment contributes not only to the
understanding of why and how these new quasicrystals form, but
also to our knowledge about the structure of molten alloys.
Scientists hope to gain insight into how atoms cluster together
and eventually grow into a crystal, a process called
nucleation.
Operations: Spherical samples of aluminum-copper-cobalt and
aluminum-copper-iron about three-eighths of an inch in diameter
(8 to 10 mm) will be levitated, melted and solidified at
different temperatures using the TEMPUS. The samples will be
analyzed post flight and the temperature, pressure and
acceleration data recorded during the STS-65 flight, will be
studied.
Thermodynamics and Glass Formation in Undercooled Liquid Alloys
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Hans J. Fecht
Technical University-Berlin
Berlin, Germany
Metallic Glass Research in Space: Thermophysical Properties of
Metallic Glasses and Undercooled Alloys
Experiment Facility: TEMPUS
Principal Investigator:
Dr. William L. Johnson
California Institute of Technology
Pasadena, Calif.
The objective and significance of Dr. Johnson's, as
well as Dr. Fecht's investigations, are quite similar. The
experimenters share their data and results, which is why they
also can be described together. Dr. Fecht's experiment uses
three alloys: zirconium-iron, zirconium-cobalt and zirconium-
nickel. Dr. Johnson's alloys are zirconium-nickel and niobium-
nickel.
Objective: This experiment uses a new mathematical method,
termed the AC method, to calculate heat capacity, an important
physical characteristic of metallic alloys cooled to
temperatures below the point when they would normally solidify.
While the formula has been evolving over several years, this
will be the first time it has been used to determine heat
capacity. This is possible because pure molten alloys can
remain liquid at cooler-than-normal temperatures when they are
suspended in a containerless processing environment such as
that provided by the TEMPUS facility.
Science: A key point in understanding the physics of this
experiment is that undercooled metals can remain molten many
degrees below the temperature at which they normally start to
form a solid crystal. At these reduced temperatures, areas
with a glass-like quality can form in zirconium-based alloys.
While these are not transparent, they are referred to as glass
because the atoms are arranged in a similar pattern as glass
used for windowpanes. The angles at which atoms are joined is
not regular; in fact, the atomic structure has no long-range
order at all.
As short, repetitive bursts of heat are rapidly
applied to the alloy sample, its temperature will
correspondingly rise and fall. This temperature increase or
decrease lags slightly behind the influx of heat, which is
modulated through the metal in a wavelike fashion. The time
difference between the addition or subtraction of heat and the
resulting temperature fluctuations is directly related to the
alloy's heat capacity, defined as the amount of heat required
to increase the temperature of 1 gram of material by 1 degree
Celsius. Scientists will use specially designed computer
software to determine the heat capacity from this temperature
lag.
Significance: Understanding the fundamentals of undercooling
and formation of metallic glasses is vital for designing such
materials. They may find applications in many technological
areas because of their unique mechanical and physical
properties. Some present areas of application include high-
powered laser choke switches, transformer cores, brazing
alloys, wear-resistant coatings, and reinforcing fibers in
metal matrices. In the future, these injection-molded, bulk
metallic glasses could influence the state of materials science
and engineering.
Operations: The pure metal samples and the alloys will be
levitated and heated above their melting point and then allowed
to cool until they solidify. These experiments involve a
series of melting-solidification.
Viscosity and Surface Tension of Undercooled Melts
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Ivan Egry
DLR Institute for Space Simulation
Cologne, Germany
Measurement of the Viscosity and Surface Tension of Undercooled
Melts under Microgravity Conditions and Supporting
Magnetohydrodynamic Calculations
Experiment Facility: TEMPUS
Principal Investigator:
Dr. Julian Szekely
Massachusetts Institute of Technology
Cambridge, Mass.
The experiments of Drs. Egry and Szekely show the
same area of specialization and follow identical procedures.
Therefore only one description is necessary to explain the
background and the goal of these experiments. Dr. Egry uses
samples of the system gold-nickel; Dr. Szekely uses gold-copper
samples.
Objective: The aim is to gain a better understanding of
microscopic interactions within molten metals, such as gold, in
the unusual condition of undercooling. This experiment
specifically focuses on studying viscosity and surface tension
characteristics. Such measurements on undercooled metals have
never before been possible. On the ground, gravity distorts
the molten sample, making it difficult to determine what is
taking place at the atomic level.
Science: The study of viscosity and the measurement of surface
tension have to do with microscopic interactions within molten
metals. Materials that have high viscosity are thick and flow
slowly, such as molasses and 50-weight oil as compared to 10-
weight oil. Materials with low viscosity are thin and flow
readily, such as water. A droplet made up of gold atoms has an
even lower viscosity and therefore is expected to take a long
time returning to a stable, non-oscillating sphere.
Surface tension is the force acting in the surface of
a liquid -- similar to a membrane -- that causes a quantity of
liquid to try to minimize its total surface area. For example,
it causes a drop to be spherical, in the absence of gravity.
When a liquid drop is levitated and its normally
spherical shape is disturbed, it will return to a sphere
through a series of oscillations. The surface tension may be
deduced from the frequency of the oscillations. Viscosity can
be determined from the rate at which these oscillations slow
down to a stable spherical shape.
Significance: Understanding the underlying principles
governing thermophysical properties of liquid metals, in
particular, viscosity and surface tension, is a matter of high
scientific interest and of benefit to industries, such as
electronics and manufacturing.
Knowledge of the viscosity of melts below the
temperature at which they solidify will make an important
contribution to the study of fluid dynamics of undercooled
liquid metals. The growing field of electromagnetic processing
of materials, especially the area of electromagnetic shaping of
electrically conducting fluids, will benefit from this
research.
Operations: This experiment will levitate and heat a gold-
copper alloy sample and a pure copper sample. Then the heating
unit will be switched off, and the liquid metal will be cooled
below its melting point. At predetermined temperatures, the
sample will be squeezed by pulsing the heating coils, thus
producing oscillations in the sample. When the squeezing force
is switched off, scientists on the ground will monitor the
frequency and rate of decay of the oscillations until the metal
sample becomes stable and stops oscillating.
Free Flow Electrophoresis Unit (FFEU)
Payload Developer: NASDA
Objective: The Free-Flow Electrophoresis Unit is being used to
study whether space-based electrophoresis will improve the
purity of certain biological materials which are normally
difficult to separate on Earth. Electrophoresis is a process
that separates biological materials into individual components
using electric fields. The method is widely used with gel
matrix in the DNA sequence analysis and clinical diagnosis.
Significance: Widely used Earth-based electrophoresis is run
in a gel matrix providing better separation, but limited for
only small molecules. Matrix free free-flow electrophoresis,
however, tends to remix the components during separation.
Gravity-induced fluid movements such as convection (fluid flows
caused by density differences) and sedimentation (settling of
heavier components) tend to remix the components during
separation. This prevents the production of suitable
quantities of very pure substances. In space, however, with
gravity no longer a dominant factor, these effects are minimal.
In space, other physical processes affecting the
separation of molecules, which are masked by gravity on Earth,
become more apparent. Scientists are interested in how these
effects might influence future space-based electrophoresis.
They also can use what they learn to better understand
electrophoresis processes on Earth.
Science: Particles of any element or compound have an
electrical charge. When exposed to an electric field, a
charged molecule of an element will move toward the side of the
field with the opposite charge. Eventually, all the molecules
within a fluid will segregate according to their charge.
Molecules separate not only according to whether they
are positively or negatively charged, but also according to the
strength of the charge and the size of the molecule. Molecules
with greater positive or negative charges move more quickly
than those with less charge. Movement of larger molecules is
slowed by increased resistance from the solution in which they
are suspended.
During electrophoresis separation on Earth, gravity
introduces flows which mix and disperse components of a
solution. For molecules with nearly the same charge, the fluid
movement is a more powerful influence than the tug of the
electric field. Microgravity virtually eliminates these flows,
making possible more thorough separation and thus more pure
materials.
Background: This facility is furnished by the National Space
Development Agency of Japan. Along with the Thermoelectric
Incubator, Cell Culture Kits and the Aquatic Animal Experiment
Unit, it was part of the First Material Processing Test P Life
Sciences which flew aboard Spacelab-J in 1992. IML-2
experiments will add to experience gained during the earlier
mission to evaluate how much microgravity increases the
effectiveness of electrophoretic separation.
McDonnell Douglas Corp. flew a Continuous Flow
Electrophoresis Experiment on several Space Shuttle flights in
the early 1980s.
Operations: The Free Flow Electrophoresis Unit separates and
analyzes the distribution of materials in a solution, using a
method called continuous-flow electrophoresis. In this method,
material to be separated is placed into a moving stream of
buffer solution. As the material passes through an electric
field, the components separate into individual streams within
the solution. The constant flow of material allows processing
of large quantities of product.
Three types of buffer solutions are contained in
separate tanks. A crew member will inject the biological
sample into the main electrophoresis unit, along with the
selected buffer solution. The astronaut then will apply an
electric field across the flowing solution stream to charge the
particles suspended in it. Individual components within the
mixture will separate into sub-streams, based on their relative
charge and size, then flow into up to 60 separation collection
tubes which can be stowed for post-flight analysis.
The crew in space and scientists on the ground
monitor progress of the experiment through a display window at
the top of the facility. Depending on the samples being
studied, they can determine concentrations of the various
separation products by how they scatter light or by how much
ultraviolet light the products absorb.
Gravitational Role in Electrophoretic Separations of
Pituitary Cells and Granules
Experiment Facility: FFEU
Principal Investigator:
Dr. Wes Hymer
Pennsylvania State University
University Park, Pa.
Objective: This experiment will use electrophoresis to
separate pituitary cells which produce different hormones into
single hormone producing components. The results will evaluate
whether separation in microgravity is superior to separation on
Earth. In addition, the experiment will help determine how
pituitary growth hormone and prolactin, an immune-system
controller, are affected by spaceflight.
Science: The pituitary system produces many hormones which
regulate how the body functions. Two of the hormones which are
produced throughout life are growth hormone and prolactin.
Growth hormone not only promotes development of long bones
during adolescence; it also increases muscle mass and promotes
the breakdown of fat in adults. Prolactin plays a part in
controlling the immune system and stimulating milk production
in women after birth. Growth hormone and prolactin come from
types of specialized pituitary cells which manufacture the
hormones and store them in secretory granules inside the cells
before release into the bloodstream.
Microgravity has been shown to negatively influence
parts of this system in humans and animals. This experiment
will attempt to determine whether the changes observed in
pituitary cells after spaceflight are caused by an alteration
to the surface of the cell, or by changes within the internal
cell structure.
Significance: In addition to furthering scientific knowledge
of electrophoresis techniques, this experiment will shed light
on how spaceflight affects growth hormone and prolactin-
containing cells and granules, information important to the
long-term health of space travelers.
Background: Dr. Hymer studied rats from two Russian Biocosmos
missions and from the 1985 Spacelab 3 mission. Post flight
studies in each instance showed the rats' pituitary cells were
less active after exposure to microgravity. Hymer's Shuttle
middeck experiment aboard STS-46 in 1992 flew rat pituitary
cells only, but the same changes occurred. This experiment
takes his research to the next step, to help determine the
reason for the changes.
Operations: Rat pituitary cells loaded in three cell culture
chambers are the samples for this experiment.
Products of cells from one chamber will be stored in
the Thermoelectric Incubator at 98.6 degrees Fahrenheit (37 !C)
for most of the mission. Astronauts will periodically extract
samples of the cell products with a syringe and refrigerate
them for post flight analysis. Scientists will use these
samples to determine structural and functional changes induced
by various durations of exposure to microgravity.
A crew member will separate cells carried in the
second chamber into 30 Free Flow Electrophoresis Unit tubes.
These 30 samples will be cultured in space to determine how the
cells function after separation.
On Flight Day 5, pituitary cells from the third
chamber will be broken apart into sub-cellular particles.
Electrophoresis will be used to separate prolactin and growth
hormone granules. The granules will be frozen for post flight
analysis to determine if internal changes occurred during the
first five days of flight.
Separation of Chromosome DNA of a Nematode,
C. elegans, by Electrophoresis
Experiment Facility: FFEU
Principal Investigator:
Dr. Hidesaburo Kobayashi
Josai University
Saitama, Japan
Objective: This experiment will employ a sensitive method for
electrophoresis called isoelectric focusing to separate
chromosome DNA from a nematode worm.
Electrophoresis is a process for separating
biological materials into individual components using electric
fields. This experiment uses isoelectric focusing, one of
several methods for performing continuous flow electrophoresis.
Isoelectric focusing is an advanced electrophoresis technique
for producing very pure separations of proteins, viruses, cells
and other biological materials on a small scale.
Science: Chromosome DNA, or deoxyribonucleic acid, is the
element of a cell nucleus which is the molecular basis for
heredity in many organisms. The small nematode is an excellent
animal for studying the genetic basis for animal development.
It is transparent, and its cellular structure is simple, with
just six chromosomes.
Because chromosome DNA has nearly constant electric
charge density, it cannot be separated from tiny organisms like
the nematode worm using standard electrophoresis techniques.
Therefore, this experiment will separate the nematode
chromosomes based upon their molecular sizes and minimal charge
differences. Since there is no gravity-induced convection or
mixing in space, the electric charge should be dominant,
resulting in a successful separation.
Normally, the solution in which samples are suspended
for electrophoresis has a uniformly neutral pH (acid/alkaline)
level. In isoloelectric focusing, the pH is graduated from
more alkaline to more acidic levels across the buffer solution.
The speed with which various molecules move during separation
varies according to buffer solution pH levels. Different
molecules stop moving, or reach their "isoelectric point," at
known pH levels. Therefore, scientists design isolectric
focusing experiments so motion of the material they want to
collect halts at a given pH level, and unwanted materials pass
on to different parts of the buffer solution.
Significance: The ability to separate chromosomes and test the
method in space may help solve problems in genetic mapping and
molecular biology.
Operations: An astronaut will inject concentrated suspensions
of chromosome DNA into the Free Flow Electrophoresis Unit,
along with a special buffer solution designed to test
isoelectric focusing.
The solution will create a pH (acid/alkaline)
gradient in the flow to allow separation of materials with
small charge differences. After the suspensions are separated,
the astronaut will stow the products in separation tubes for
post flight analysis. Investigators on the ground will subject
the chromosomes to standard genetic and biochemical tests.
Experiments Separating the Culture Solution of Animal Cells
in High Concentration under Microgravity
Experiment Facility: FFEU
Principal Investigator:
Mr. Tsutomu Okusawa
Hitachi, Ltd.
Ibaraki, Japan
Objective: This experiment grows animal cells in cultures,
then separates their cellular secretions in the Free Flow
Electrophoresis Unit. Animal cells synthesize substances which
can be valuable medical drugs. Investigators believe that two
fundamental aspects of pharmaceutical production, the rate of
separation and the amount of separated product, may be improved
by space processing.
Electrophoresis is a process for separating
biological materials into individual components using electric
fields. It is expected that the method is useful in the
production and purification of drugs and medicines on Earth.
Science: Drugs expected to work for cancer diagnosis and
treatment include monoclonal antibodies, which are effective
for both treatment and prevention because they provide a
disease immunity. These antibodies are obtained from cultured
animal cells on Earth. In the present commercial production
method, animal cells are multiplied to the highest
concentration possible in cell cultures. A recent method for
culturing animal cells on the ground is being used to grow
cells at ten times the previous rate. Then, the useful
substance is separated from the culture medium through a
refining process. After the medium is passed through a series
of filters, final removal of unnecessary substances is
accomplished by a process called liquid chromatography.
However, the method is complicated and inefficient. The
substances must be refined further to obtain a pure
pharmaceutical product in larger quantities.
Ground-based electrophoresis has been used to analyze
the separation process. It has not been practical for
commercial processing, though, because convective flows within
the separation fluid caused by gravity reduce its
effectiveness.
Separation by electrophoresis in space shows promise
for yielding larger amounts of a purer product. In addition,
previous experiments indicate that the cells may produce
antibodies at much faster rates in microgravity.
Significance: Results from experiments such as this should
verify the validity of the electrophoresis method in space and
provide useful knowledge for establishing space-based
biotechnology production in the future.
Operations: A crew member will place one type of hybrid animal
cell from the Cell Culture Kits into the Thermoelectric
Incubator, both IML-2 life-science equipment furnished by the
Japanese Space Agency. The culture will incubate and grow for
five days. Then, the highly concentrated cell solution will be
injected into the Free Flow Electrophoresis Unit, where the
cellular secretions will be separated from the solution.
The sample will be separated under three different
conditions, varying flow rates and the timing and intensity of
electrical charges. The crew member operating the experiment
and ground controllers will determine which conditions proved
the most effective. The fractions of the sample separated
under those conditions will be collected and frozen for post-
flight analysis.
Aquatic Animal Experiment Unit (AAEU)
Payload Developer: NASDA
Objective: The facility provides an environment supporting
studies of live fish and small amphibians under microgravity
conditions. It permits observations of spawning,
fertilization, embryonic stages, vestibular functioning and
behavior in microgravity.
Hardware: This aquarium consists of two independent life-
support systems, called fish and aquarium packages.
Small fish and amphibians, such as newts, live in
four cassette-type aquariums, and there is a larger tank
designed for fish. A special life-support system supplies
oxygen, removes carbon dioxide and waste (such as ammonia and
organic substances), and regulates the temperature as desired,
between 59 and 77 degrees Fahrenheit (15 to 25 degrees C). The
crew can view the animals through a window and access them by
means of a port in each enclosure.
A video system can be attached to the viewing port
for recording observations of behavior, such as swimming
patterns. Closeup observations can be made of fertilization
and embryonic development. These images, along with
housekeeping data on water temperature and pressure and other
parameters, are downlinked to scientists supporting the mission
on the ground.
Background: The AAEU was flown successfully on the Spacelab-J
mission (STS-47), in a slightly different configuration. It
was referred to as the vestibular function unit, and supported
studies with carp.
Mechanism of Vestibular Adaptation of Fish under Microgravity
Experiment Facility: AAEU
Principal Investigator:
Dr. Akira Takabayashi
Fujita-Gakuen Health University
Toyoake, Japan
Objective: This experiment further explores the hypothesis
that space motion sickness is caused by conflicting messages
sent from the eyes and the otoliths. Investigators expect to
clarify the interaction between otolith organs located in the
inner-ear and other gravity-sensing organs. Six goldfish will
be used to study how their vestibular systems adapt to
microgravity and readapt to Earth's gravity after landing.
Significance: Space motion sickness usually is experienced by
roughly half of all human space travelers, and may occur in
other species. The investigator's team wants to evaluate
mechanisms which may cause space motion sickness. This will
help the effort to develop preventive measures.
Science: On the ground, animals control their posture and
motion by sensing gravity by means of their vestibular and eye
system. Posture control is achieved by integrating information
in the brain received from both the eyes and vestibular system.
When animals are placed in microgravity, they tend to lose
their balance, then gradually adapt with time.
The most important gravity-sensing mechanism is the
vestibular-otolith system in the inner ear on both sides of the
goldfish. However, in microgravity, goldfish might maintain
their balance only by visual input.
Background: This experiment is an extension of an experiment
flown as part of Spacelab-J (STS-47).
Operations: In goldfish, the vestibular apparatus contains two
otolith organs. Before launch one or both otoliths will be
removed by surgery from five goldfish; a sixth goldfish will
have both otoliths intact. All six goldfish will be flown in
the Aquatic Animal Experiment Unit.
The fish behavior will be videotaped once a day and
analyzed after the mission. One aspect of behavior to be
observed is how the fish react to light stimulation from a
direction perpendicular to the aquarium (dorsal light
response). Swimming patterns, including measurements of the
tilting angle, velocity, and how these characteristics change
over time, will be studied to learn how the fish adapt in
microgravity.
After Columbia lands, the readaptation process to
Earth's gravity will be observed for 10 days.
Otoconia: Early Development of
A Gravity-Receptor Organ in Microgravity
Experiment Facility: AAEU
Principal Investigator:
Dr. Michael L. Wiederhold
University of Texas Health Science Center
San Antonio, Texas
Objective: The purpose is to study how the gravity-sensing
organs located in the middle ear develop in microgravity using
embryos of the Japanese red-bellied newt. Scientists will
study the development of both the gravity-sensing otolith
organs and angular-acceleration sensors, the semicircular
canals.
Science: All vertebrates (creatures with a spinal column) and
most invertebrates have specialized receptors in their inner
ears to sense gravity. In many organisms, including humans,
this gravity perception occurs in organs known as otoliths.
The organ contains mineral crystals called otoconia. The organ
detects gravity by an interaction of the otoconia and tiny
hairs (cilia) inside the inner ear. The crystals have greater
density than the fluid surrounding them, so gravity pulls them
down. The fall of the crystals (stones) on the hairs deflects
hair bundles on top of the hair cells, causes excitation of
vestibular-nerve fibers to the brain indicating body position.
There is uncertainty about how the crystals, their
associated receptor cells and the connections of the nerve
fibers within the brain develop in space without gravity.
The investigator's team wants to clarify this reflex
process and also study growth development in the absence of
gravity.
Significance: Observations should clarify gravity-dependent
vestibular information processing. These findings will help
explain the fundamental role of gravity on the otoliths and how
it affects development of balance control.
Operations: The development process of the vestibular system
including rotational acceleration sensors or semicircular
canals will be investigated using Japanese red-bellied newts.
Newts are very suitable for this experiment because these
animals' vestibular system can develop within the planned IML-2
mission duration of 14 days.
Female newts will be used, since they store the
fertilized eggs in their bodies. The crew injects some of the
newts with a hormone during the spaceflight to observe the
early development of the gravity sensor in an embryo grown in a
microgravity environment. The size of the otoliths and
associated sensory structures will be determined by three-
dimensional reconstruction of sections of the inner ear.
The rate of calcification will be determined by
labeling new calcium deposits with two different fluorescent
calcium-binding dyes applied four days apart. Otolith function
will be assessed by examining the newts' larvae vestibular-
ocular reflex.
Data from the newts flown in microgravity will be
compared to controls on the ground, to embryos whose growth
began three to five days before launch, and to newt embryos
whose growth began on orbit. By comparing these groups, the
investigators can determine if otoconial formation proceeds
normally in microgravity.
Fertilization and Embryonic Development
of Japanese Newts in Space
Experiment Facility: AAEU
Principal Investigator:
Dr. Masamichi Yamashita
Institute for Space and Astronautical Science
Kanagawa, Japan
Objective: Unique aquatic animals will be used to investigate
the effects of gravity on cells during early developmental
stages.
Science: Previous experiments have indicated that gravity
affects amphibian eggs before their first cleavage. A single
egg divides into many cells, and those cells mature or
differentiate to form all the organs whose function makes up
the living organism. Gravity is one factor that regulates this
process. By studying cell differentiation in microgravity,
scientists may be able to determine the effects of gravity on
cells at early developmental stages.
The Japanese newt starts its life from a large,
single-cell egg. Gravity plays a role in the egg's development
by orienting the heavy vegetal hemisphere of the egg downward.
Early stages of development may be very sensitive to gravity.
This may occur even before the single cell divides into two
cells. To investigate this effect, scientists will study newt
eggs exposed to microgravity.
Significance: Fertilized newt eggs will be observed during the
most dynamic stage of their life. Findings on the effects of
the absence of gravity on their early development could help
scientists acquire knowledge about the benefits of Earth's
gravity for a biological system in early developmental stages
and the mechanisms involved.
Background: The experiment on IML-2 may enrich scientific
results and provide a larger number of specimens to establish a
good statistical base. It also provides an opportunity to
compare data from independent experiments. This "AstroNewt"
experiment also is scheduled to fly on the first mission of the
Space Flyer Unit. This Japanese space platform will be
launched by an H-II rocket.
Operations: Japanese red-bellied newts mate in the autumn.
The female newts go into hibernation, storing sperm in their
bodies for fertilizing their eggs in the springtime. The
hibernating newts will be collected and stored under controlled
conditions until just before the STS-65 launch. Hibernation
can be successfully terminated at any time by warming the
creatures to 59 degrees Fahrenheit (15 degrees Celsius).
During the IML-2 mission, four newts will be kept in
three water tanks in the Aquatic Animal Experiment Unit onboard
Columbia. The female newts will be induced by a hormonal
treatment to lay eggs in the water tanks. Two newts will
receive a hormone injection on the ground prior to launch.
This should result in their laying eggs three to four days
later. Crew members will inject the other two newts in space.
When space-borne eggs are obtained, those eggs are
isolated from the mothers by a partition. Close-up video
images of the eggs and embryos will be recorded to trace their
time course of development.
Some embryos will be preserved at specific
development stages, while some will continue further
development after Columbia lands. They will be kept until they
hatch on Earth for the morphological and behavior studies.
A simultaneous control experiment will be conducted
on the ground.
The adult newts and eggs will be shared with Dr.
Wiederhold's "Otoconia" experiment.
Mating Behavior of the Fish (Medaka) and Development of
Their Eggs in Space
Experiment Facility: AAEU
Principal Investigator:
Dr. Ken-ichi Ijiri
University of Tokyo
Tokyo, Japan
Objective: To study whether the freshwater fish, Medaka, can
mate and lay eggs under the weightlessness conditions of
spaceflight. If eggs are laid, scientists will study their
development. The swimming behavior of this special strain of
Medaka also will be observed during and after the flight.
Significance: Aquaculture in space could become an important
nutritional theme in the future. Fish may be included in a
controlled ecological life-support system being developed for
long-term human stays in space.
In a practical system, fish would mate and spawn
eggs, thus increasing their numbers. This experiment tests the
feasibility of such an aquaculture design in microgravity,
checking the mating behavior and embryonic development of a
small fish. Results may help scientists plan other experiments
for breeding fish in space.
Science: Medaka is a small freshwater fish commonly found in
ponds and rivers all over Japan's countryside. It is an
excellent experimental species because it has a relatively
short life cycle of three months from one generation to the
next. Also, the transparent body provides for easy observation
and identification of its organs during embryonic development.
Therefore, scientists can determine whether microgravity
impacts normal development processes.
Fish usually swim in loop patterns when they are
exposed to microgravity. However, a special breed of the
Medaka species has not exhibited this behavior when exposed to
microgravity for short periods of time on parabolic flights
aboard aircraft. This tolerance to microgravity should be
inherited by future generations of this breed. This experiment
will examine whether this strain continues to swim normally
during a longer stay in space.
Operations: Two pairs of male and female Medaka will be
transferred to a small cassette-type aquarium about two days
prior to launch. The life support for the Medaka is
continuously provided by the Aquatic Animal Experiment Unit for
the entire mission.
Each day, mating behavior should be completed within
two hours after the transition from a 10-hour dark period to
light period. After crew members visually verify the first
spawning onboard Columbia, a video camera will record activity
for the first two hours of the light period, which should be
enough time to record the fish mating behavior.
Once spawning starts, the fish will continue to lay
eggs once every day for a month. Newly laid eggs first form a
cluster on the belly of the female fish. After a few hours,
the eggs fall away from her body. The detached eggs should
flow with the water into an area separated by a mesh structure.
The crew will continue video observations of the developing
embryos at predetermined intervals. Detailed observations of
its early embryonic development are possible because the egg
envelope is transparent. The fry are expected to hatch about
eight days after spawning. Investigators expect to see hatched
fry swimming in the aquarium during the mission. They also are
interested in the swimming behavior of the fry and adults after
Columbia lands.
Genetic studies of the fish will be conducted post
flight. Computer analysis of fish movement based on the video
images recorded on the ground and in orbit is also planned.
Applied Research on Separation Methods Using
Space Electrophoresis
Recherche Appliquee sur les Methodes de Separation en
Electrophorese Spatiale (RAMSES)
Payload Developer: The French Space Agency (CNES)
Objective: Scientists will conduct experiments using RAMSES to
better understand the basic mechanisms that govern
electrophoresis and assess gravity's impact on the process.
Separating and collecting ultra-pure components of biological
substances is an area of research with great importance to the
pharmaceutical industry. Electrophoresis is a process for
separating biological materials into individual components
using an electrical field. These purified materials can then
be used for other processes, such as growing crystals. This
technology has been adapted for use in microgravity in the
RAMSES electrophoresis unit. RAMSES is the French acronym for
Applied Research on Separation Methods using Space
Electrophoresis. This multi-user facility was developed by the
French Space Agency in conjunction with European industrial
partners.
Gravity-induced fluid movements such as sedimentation
(settling of heavier elements in the solution) and convection
(flows within fluids caused by temperature and concentration
differences) tend to remix the compounds during separation on
Earth. RAMSES will allow researchers to escape these limits by
taking advantage of the reduction of gravity-induced phenomena
in space.
The basis of the electrophoresis separation process
is complex. Biological molecules in a fluid carry electric
charges. Each type of molecule moves within an electric field
at different speeds depending on its charge polarity, size and
shape. For example, a molecule that is very negative will feel
greater attractive and repulsive forces from the electric field
than a slightly negative particle. Consequently, it will move
more quickly than the molecule possessing less charge. The
fluid in which the particles are suspended also plays a role in
this process. The viscosity of the fluid or carrier solution
hinders the forward movement of large molecules.
With the virtual absence of convection and
sedimentation in microgravity, other important phenomena
normally masked by gravity come into play, affecting the
separation of molecules. Scientists are particularly
interested in these electro-hydrodynamic effects. These are
rotating movements of the liquid that are produced by the
electric field.
Hardware and Operations: RAMSES is a continuous flow
electrophoresis unit, meaning the biological sample to be
purified is continuously injected into a carrier solution
flowing up the length of a transparent separation chamber. An
adjustable electric field is applied across the flow, causing
the differently charged components to diverge into a wide beam
consisting of separate streams. The separated streams of
molecules pass through 40 outlets into collection tubes. A
light absorption instrument, called a photometer, monitors the
process. When it detects a significant concentration of
biological material in the outlet flow, crew members will
recover those collection tubes which, after storage in a
refrigerator, will be returned for analysis. Otherwise the
flow is diverted to a waste tank.
Separation parameters -- flow rates, electric field
strengths and carrier fluid temperature -- can be altered to
study a wide range of conditions. This will allow the optimum
separation conditions to be determined. Crewmembers can
monitor the separation experiments and photograph them through
a transparent window in the instrument front panel. A
specialized light source provides a "sheet" of illumination
across the separation chamber, producing a cross-sectional view
of the sample flow behavior.
The RAMSES Control Command and Acquisition System
directs the operation of the complete system. It provides the
user interface, acquires and stores experiment data, and
provides connections with the science team on the ground. Crew
members can also make adjustments. The crew will be
responsible for setting up operations, monitoring the
separation process and the photometer which indicates the
collection tubes that are gathering the highest quality
samples. These are the samples that will be returned to
scientists on the ground for further research.
Optimization of Protein Separation
Experiment Facility: RAMSES
Principal Investigator:
Dr. Victor Sanchez
National Center for Scientific Research (CNRS) Chemical
Engineering Laboratory
University Paul Sabatier, Toulouse, France
Objective: This investigation will use a unique process to
separate protein solutions into individual components using an
electric field. The process is called electrophoresis.
Solutions of proteins will be purified by separating them into
several streams, each one containing proteins of only one kind.
Just one milligram (a thirty thousandth of an ounce) of protein
purified for use in pharmaceuticals can be very expensive.
Performing this purification in the absence of gravity may
allow scientists to gather purer protein in larger quantities
than is possible on Earth.
Two series of experiments will be conducted to
evaluate the degree of protein purification that is possible in
microgravity. Three samples each contain two pure proteins
that have been mixed together. This will allow the process to
be tested with well-known products. Three other samples
contain a great number of proteins extracted from a bacterial
culture. Here most of the proteins are unidentified, and
scientists are interested in how these solutions will separate.
Another objective is to test whether the biological activity
remains intact in the purified product.
Science: A protein molecule is a complex structure that has an
electric charge. Each type of protein moves at a different
rate across the chamber when exposed to an electric field.
Therefore, when a solution of protein molecules is passed
through a separation chamber, the molecules will move away
from the side with the same charge toward the opposite-charged
side of the field. The particles will separate and fan out
into an array of bands as they flow through the chamber. At
the outlet they can be collected for further research.
The principal investigator's team hopes to study a
three-fold combination of effects:
% how the separation process is affected by the
strength of the electric field and by the length of time spent
traveling through it
% how the protein molecules interact with ions and
molecules of the carrier solution
% electro-hydrodynamics, a rotating movement of the
carrier liquid caused by disturbances in the electric field due
to the presence of the protein.
Significance: Tomorrow's pharmaceuticals will be developed
using proteins produced by biotechnology. Therefore,
scientists require a precise knowledge of protein structure.
To obtain this, highly purified protein molecules are necessary
in sufficient quantity to allow protein crystals to be formed.
Working in microgravity eliminates buoyancy forces,
allowing scientists to use more highly concentrated protein
solutions, higher electric field strengths and slower carrier
flow rates for longer separation times.
Background: IML-2 scientists will build on past progress with
continuous flow electrophoresis operations in microgravity by
studying a variety of biological materials and further
characterizing this type of processing and the operating
conditions that affect it. Investigations into electrophoresis
for separating biological materials began in the 1950s.
McDonnell Douglas Corp. conducted several experiments onboard
the Space Shuttle during the 1980s. This French team of
investigators became interested in this process in the mid-
1980s.
Operations: In continuous-flow electrophoresis, a stream of
carrier solution flows through a thin, rectangular chamber.
When a protein mixture is injected into this flowing solution,
it moves with the flow and an electric field causes the
proteins to move apart across the width of the chamber. A
direct current field is used here to keep the proteins always
moving in the same direction. A photometer (measuring light
absorption) will be used during operation for measuring protein
concentrations in the 40 samples. A crew member will
refrigerate the samples with the highest protein
concentrations, which will be returned for post flight
analysis. The first sample to be treated will contain two
colored proteins. These are easily separated and will be
processed under the same conditions as on Earth. This will
demonstrate that the instrument is operating correctly on its
maiden flight. This instrument can treat up to one milligram
of protein per hour, which is considered a large amount of
matter.
Electrohydrodynamic Sample Distortion
Experiment Facility: RAMSES
Principal Investigator:
Dr. Robert Snyder
NASA Marshall Space Flight Center
Huntsville, Ala.
Objective: This experiment focuses specifically on electro-
hydrodynamics. This is the movement of liquid driven by an
electric field. In this case, the movement will be made
apparent by the use of a suspension of latex particles in
liquid. Scientists will examine how the shape of a stream of
particles is modified by an electric field.
Electro-hydrodynamic effects are more easily observed
in the absence of gravity, where convection caused by buoyancy
is virtually eliminated. Sedimentation, the settling and
separation of heavier elements from lighter ones, also is
greatly reduced. The principal investigator's team plans to
stop the flow of a carrier liquid and immobilize the stream of
latex particles. On Earth, the particles would immediately
settle to the bottom of the chamber. In microgravity, the
originally cylindrical stream of particles should be deformed
by the electric force without interference from any other
movement.
Significance: Continuous-flow electrophoresis is a process
that allows protein mixtures, or living cell populations, to be
separated into batches of highly purified products in
sufficient quantity for them to be used in other processes,
such as protein crystallization.
However, before highly concentrated samples can be
processed on a large scale, the factors governing
electrophoresis must be more fully understood. One is the
electro-hydrodynamic spreading of a sample stream in
electrophoresis, resulting in remixing of the components that
are meant to be separated, thus harming the purity of the
product.
Improved understanding of the physics underlying
electro-hydrodynamics will help scientists better control this
phenomenon and thereby improve the separation in
electrophoresis. Microgravity allows highly concentrated
samples to be used and observations to be made even when the
carrier flow is entirely stopped.
Science: Latex particles are bigger and less complex in
structure than protein molecules so they are easier to study.
Like proteins, the latex particles retain a positive or
negative charge. This means that they also can be influenced
by an electric field.
The electric field around a stream of latex particles
can be distorted either by varying differences in electrical
conductivity or by using differences in dielectric constant.
The manipulation of electrical conductivity in the liquid
results in local areas through which electric current passes
more easily, and areas of greater opposition to current flow.
The result is a non-uniform field in the liquid.
The dielectric constant involves the way in which
molecules or particles tend to be oriented by an electric
field. A non-uniform field causes the liquid in and around the
latex-particle stream to rotate, showing up as a change in
shape of the stream of particles.
Background: Electro-hydrodynamic effects such as these were
originally observed in the 1960s. Previous continuous-flow
electrophoresis experiments exhibited electro-hydrodynamic
spreading of the sample stream when electrical properties (such
as conductivity and dielectric constant) of the sample stream
were not the same as those of the carrier solution.
Operations: Two different samples will be used to study the
effect of varying the latex-particle concentration. The
suspension of latex particles will be injected into a carrier
solution flowing through the separation chamber of the RAMSES
electrophoresis unit.
The first part of this experiment uses AC fields, in
which the positive and negative poles of the field are rapidly
switching. The latex particles should not exhibit any net
movement, allowing the electro-hydrodynamic effect itself to be
observed. As the solution flows through the chamber it should
widen into a continuous ribbon of latex particles. A thin
sheet of light will illuminate a cross-section of this ribbon
so that a crew member may view and photograph any distortions
to the flow of latex particles.
Advanced Protein Crystallization Facility
Payload Developer: European Space Agency
Objective: Advanced Protein Crystallization Facility (APCF)
research has two objectives: to provide difficult-to-produce,
biologically important protein crystals for analysis, and to
determine the physical mechanisms that govern protein crystal
growth. It is the first space facility ever designed to use
three different protein crystal growth techniques.
Significance: Proteins are complex molecules responsible for a
great many biochemical functions essential to life on Earth.
Scientists strive to determine the structure and function of
proteins to better understand living systems and to develop
medicines. For example, the pharmaceutical industry uses
structural information to design drugs which bind to a specific
protein, blocking chemically active sites. Such a drug fits a
protein like a key in a lock to "turn off" the protein's
activity, thus regulating metabolic processes.
The three-dimensional structures of proteins are
determined by X-ray analysis of protein crystals. However,
many proteins that interest medical researchers have not
produced crystals of adequate size and quality to allow X-ray
data to be collected. Crystals grown in space, where they are
virtually free from the distortions of gravity, often provide
better structural information than their counterparts grown on
Earth.
Hardware: The Advanced Protein Crystallization Facility is a
fully autonomous facility except that it requires electrical
power from the Shuttle and activation by a crew member when
orbit is reached. Temperature control, any value between 4 and
25 degrees C is possible, activation/deactivation of the
protein growth chambers, monitoring of basic housekeeping
parameters, video image taking and recording of all data on a
digital tape recorder are performed under control of a
microprocessor. Two experiment units exist, each of which
occupies one Shuttle mid-deck locker. For IML-2, both units
will be held at a constant temperature of 68 degrees Fahrenheit
(20!C). Each unit can accommodate 48 modular protein crystal
growth chambers, 12 of which can be observed with a high-
resolution, black and white video camera. Chambers for each of
the three crystallization techniques are available in different
volumes. All types and volumes of chambers are interchangeable
within the units, so researchers can choose the best
combination for their particular studies.
The three protein crystallization techniques
available to users of the facility are:
Vapor diffusion: The protein is suspended as a drop
at the end of a syringe tip in a chamber surrounded by material
soaked in a concentrated precipitation agent. As water
migrates from the protein solution to the precipitant solution,
the concentration of protein within the drop increases.
Eventually, it supersaturates, and crystal growth begins.
Liquid-liquid diffusion: The protein solution, a
buffer solution, and a precipitant solution are initially
separated by shutters. When the shutters are removed, the
precipitant diffuses through the central buffer solution into
the protein solution, causing the protein to become less
soluble and initiating crystal growth.
Dialysis: The protein solution is separated from a
reservoir of precipitating agent by a thin membrane of material
that allows passage of some substances while blocking others.
The precipitant moves across the membrane into the protein
solution, initiating crystal development.
Operations: The crew activates the Protein Crystallization
Facility after reaching orbit, monitors the facility as it
operates, and deactivates the equipment when experiments end.
No data are transmitted to the ground during the mission.
Crystal growth begins by causing a protein solution
to "supersaturate," a condition where more protein is present
than can remain dissolved within a volume of fluid. As a
result of this supersaturation, the protein crystals
precipitate out of solution and begin to grow.
Video images will be made of crystals as they form.
After the mission, the approximately 5,000 images will allow
investigators to study the history of crystal development in
microgravity.
Background: This experiment facility was developed by the
European Space Agency. It has flown once before, on the
Spacehab-1 mission (STS-57) in 1993.
Principal Investigator Proposed Protein(s)
Method
N. Chayen/P. Zagalsky alpha Crystacyanine
vapor
Great Britain diffusion
A. Ducruix/M. Ries Collagenase vapor
diffusion
CNRS Laboratory of Rhodobacter Spheroides
liquid-
Crystallography liquid
Gif sur Yvette, France diffusion
V. Erdmann/S. Lorenz RNA vapor
Free University of Berlin diffusion
Berlin, Germany dialysis
R. Gieg/A. Thobald Aspartyl-tRNA Synthetase
vapor
CNRS Institute of Molecular diffusion
and Cellular Biology dialysis
Strasbourg, France
W. deGrip/J.V. Oostrum Rhodopsin vapor
University of Njimegen diffusion
Nijmegen, The Netherlands
J. Helliwell/E. Snell Lysosyme dialysis
University of Manchester (collaboration with Sj lin)
Manchester, England
J. Martial/L. Wyns Octarellin vapor
Belgium Copperoxalate diffusion
liquid-
liquid
diffusion,
dialysis
A. McPherson/S. Koszelak Satellite Tomacco Mosaic
Virus liquid-
U. of California at Riverside Satellite Panicum Mosaic
Virus liquid
Riverside, California Cucumber Mosaic Virus
diffusion
Turnip Yellow Mosaic Virus
L. Sj lin Ribonuclease S vapor
Chalmers U. of Technology (collaboration with
Helliwell) diffusion
G etborg, Sweden
G. Wagner Bacteriorhodopsin dialysis
Justus-Liebig U. of Giessen
Giessen, Germany
Principal Investigator Proposed Protein(s)
Method
A. Yonath/H. Hansen Haloarcula marismortui
vapor
Max-Planck-Laboratory for 50S diffusion
Ribosomal Structure
Hamburg, Germany
F. Jurnak Pectate lyase liquid-
U. of California at Riverside liquid
Riverside, California diffusion
M. Garavito OmpF porin liquid-
University of Chicago liquid
Chicago, Illinois diffusion
K. Ward Aequorin liquid-
Naval Research Laboratory Phosphoilpase A1
liquid
Green fluorescent protein
diffusion
H. Einspahr Cytochrome c (tuna) liquid-
Bristol-Meyers-Squibb liquid
diffusion
P. Weber Alpha-thrombin (human) liquid-
DuPont liquid
diffusion
Bubble, Drop and Particle Unit
Developed by the ESA
Objective: Subtle aspects of fluid physics, normally hidden by
the effects of Earth's gravity, will be investigated in
microgravity with the Bubble, Drop and Particle Unit, developed
by the European Space Agency.
Researchers will study fluid behaviors and
interactions such as bubble growth, evaporation, condensation,
thermocapillary flows (fluid motions generated by temperature
differences along the surfaces of liquids). Such phenomena are
difficult to observe on Earth because their effects are masked
by gravity-induced fluid movements.
Science: Our intuitive expectations of how fluids (liquids or
gases) normally behave are based on their actions under the
influence of gravity. For example, hot air rises because it is
less dense than cooler air, and gravity's pull similarly
induces convection -- flows within a fluid caused by density
differences. Muddy water will clear when left standing because
gravity also causes sedimentation (the separation and settling
of heavier elements from lighter ones) of soil particles
suspended within the water.
In a microgravity environment, such gravity-driven
convective flows are minimized, and other more subtle fluid
movements, such as thermocapillary flows, can be observed. The
flows become the main mechanism of heat transfer within fluids.
Suspended particles, bubbles and liquid drops behave
differently in microgravity. For example, drops of liquid
become spherical, instead of teardrop, as their shape becomes
dominated by surface tension effects instead of gravity.
Significance: Results may be used to improve the design of
spacecraft life support and fuel management systems as well as
materials processing both on Earth and in space. The behavior
of fluids is at the heart of many phenomena in materials
processing, biotechnology and combustion science. Surface
tension-driven flows (fluid flow from hot regions to cold)
affect semiconductor crystal growth, welding and the spread of
flames on liquids. The dynamics of liquid drops are an
important aspect of chemical process technologies and in
meteorology.
Hardware: Crew members will exchange interchangeable
experiment test containers with dedicated fluid cells located
in the Bubble Drop and Particle Unit. The fluid cells can
incorporate mechanical or acoustic stirrers for fluid mixing,
injectors for bubbles or droplets, and heating and cooling
elements to impose temperature differences within the fluid.
Modular optics components support several different
diagnostic techniques, including Schlieren (shadowgraph),
interferometric and infrared imaging. The sample can be
illuminated using fluorescent lamps, or a Helium-Neon laser.
Experiments are automatically controlled by a microprocessor.
Investigators on the ground can monitor the processing of their
experiments and can change parameters. Crew members can also
adjust and modify conditions.
Cameras and sensors will observe and record
temperature, density, position and interactions within the
liquid-filled test cells.
Bubble Migration, Coalescence and Interaction with
Melting and Solidification Fronts
Experiment Facility: BDPU
Principal Investigator:
Dr. Rodolfo Monti
University of Naples
Naples, Italy
Objective: Bubbles form as molten alloys, crystals and glasses
begin to solidify both on Earth and in microgravity.
Scientists are interested in why these bubbles are not
uniformly distributed within the metal, whether processed on
Earth or in space. This investigation will use a transparent
material to observe the movement of bubbles at the liquid-solid
interface as the material first melts, then solidifies. It
also will study how drops of liquid behave when exposed to a
temperature gradient and interact with the solidification front
-- the moving boundary where a molten substance is
crystallizing into solid.
Significance: This research is significant for improving
techniques for material processing in space. It is important
to learn how to control the movement of bubbles in a material
during phase changes, such as from liquid to solid. Scientists
are interested in knowing how to solidify materials, both with
the bubbles included and excluded from the substance.
These findings have potential applicability for
industries in areas such as the production of crystals in
electronic devices. Another area of industrial interest is
refining the capability to disperse one material into another
with extremely high uniformity by controlling the Marangoni
migration of inclusions in melts. This is the movement of
bubbles or drops driven by surface forces when a liquid's
surface tension is affected by heat, in the form of a
temperature gradient.
Science: On Earth, gravity-induced convection and buoyancy
alter processes that would benefit from gravity- and
disturbance-free conditions. This experiment will allow
scientists to observe bubble movement and the interaction with
the solidification front in the absence of gravity with bubble-
drop dimensions not achievable on the ground.
Operations: The test sample will be a solid piece of
tetracosane, a transparent material that melts at a low
temperature. The material sample includes pre-formed bubbles
of different sizes.
The tetracosane will be heated above its melting
point 131 degrees Fahrenheit (55 degrees Celsius). As the
melting front reaches each bubble, the bubble will be released
and is expected to migrate toward the hot side of the liquid,
away from the melting front. The locations, dimensions and
movement of the bubbles released by the melting front will be
recorded. Other characteristics of the migration will be
studied and documented.
Thermocapillary Migration and Interactions of Bubbles and Drops
Experiment Facility: BDPU
Principal Investigator:
Dr. R. Shankar Subramanian
Clarkson University
Potsdam, NY
Objective: This experiment will study the movement and shape
of gas bubbles and liquid drops in silicone oil when a
temperature gradient is established within the container. The
bubbles are expected to move from a position near the cold wall
toward the hot wall. The gas bubbles and liquid drops will
have a range of diameters and densities.
Significance: Bubbles and drops are encountered in various
materials processes, such as solidification and preparation of
composite materials. Also, for long-duration space voyages,
recycling of waste material will be essential, and separation
processes used for this purpose may involve bubbles and drops.
Therefore, it is important to understand the motion of bubbles
and drops and to learn to manipulate them under low-gravity
conditions where buoyancy is negligible.
Science: Bubbles do not behave in space like they do on Earth.
By managing bubbles and drops and measuring how fast they move
because of a temperature difference, scientists may be able to
predict various engineering applications and hardware designs.
This heating and cooling simulates the melting and
solidification of metals and other basic scientific principles
used in other experiments.
The investigator's team will study how fast the
bubbles move, their size and shape. These data will be
compared with mathematical predictions.
Operations: A series of experiments, each lasting about four
hours, will be conducted. Before each series, a temperature
gradient will be established in the container. Thereafter
bubbles and drops will be injected into a small rectangular
cell filled with a fluid. Approximately six bubbles (or drops)
will be injected in sequence. Their motion will be monitored
on the ground via video. Then, the bubbles or drops will be
extracted through an extraction net, in preparation for the
next series of runs. Results from the experiments will be
compared with predictions from theoretical models. Temperature
control and bubble/drop injection can be performed
automatically and under control of the investigator on the
ground or by an IML-2 crew member.
Bubble Behavior Under Low Gravity
Experiment Facility: BDPU
Principal Investigator:
Dr. Antonio Viviani
Seconda Universita degli Studi di Napoli (SUN)
Aversa, Italy
Objective: This experiment investigates how different size
bubbles of inert gas move within a liquid. The liquid, n-
heptanol, will be subjected to an uneven temperature
distribution. The membrane encasing the gas bubble will react
to the temperature variation within the liquid. The membrane
toward the colder temperatures contracts -- a result dependent
on a surface tension change on that portion of the membrane --
causing the bubble to move.
The motion of the bubbles is driven by variations in
the surface tension, which are induced by temperature
differences along the interface (thermocapillary effect),
between the liquid and the bubble. This particular kind of
liquid permits measurement of an unusual, non-linear
temperature-dependent surface tension. The fluid region where
surface tension is at a minimum is of great interest.
Science: This phenomenon can be illustrated with an analogy.
Soiled clothes are washed in hot water which relaxes the
surface tension of the cloth fibers permitting the dirt to be
extracted. This investigation will use temperature differences
and thermodynamic principles to move and extract bubbles.
Scientists also want to determine if higher temperatures will
cause bubbles in molten glass to migrate to an exterior surface
so they can be eliminated.
Significance: Earth's gravitational field acts on density
differences between air and liquid, making buoyancy forces
predominant. In the absence of gravity, density is eliminated
and only the effects of surface tension are observed. The
effects of this phenomenon on Earth are masked by buoyancy. In
space, scientists can observe how bubble movement is affected
solely by surface tension to gain a better understanding of the
role surface tension plays on Earth.
Operations: Bubbles of inert gas will be injected into the
liquid n-heptanol under a temperature gradient. Investigators
will determine the non-uniform velocity of the injected bubbles
for different temperature ranges. They want to observe the
behavior of the bubbles when they reach the center of the
container where the surface tension will be at a minimum and
the bubbles are expected to stop.
The experiment will be repeated with several bubbles
of varying size. The temperatures of the chamber walls will be
varied. Sometimes the bubbles will move toward the hotter
chamber wall. At other times they will move toward the cold
wall.
The investigators also plan to inject two bubbles to
observe what happens when they come together. Images of the
bubble migration will be recorded and sent to investigators on
the ground. The experiment sequence is three-fold: establish
optimal temperature conditions, inject bubbles, and extract the
bubbles using a net mechanism.
Interfacial Phenomena in a Multilayered Fluid System
Experiment Facility: BDPU
Principal Investigator:
Dr. Jean N. Koster
University of Colorado
Boulder, Colo.
Objective: Even in everyday life, we frequently observe that
some fluids, such as oil and water, do not mix. Instead, they
form layers when placed in the same container. This
investigation is designed to study what is happening at the
place where the immiscible liquid molecules touch each other,
called the liquid-liquid interface, when temperature-driven
fluid motion is generated at the contact surface. The
experiment will be conducted using a multilayered immiscible
fluid system.
Science: Studying interface forces in low gravity will provide
new and fundamental insight into a complex field of fluid
physics that cannot be studied on the ground. Earth's gravity
causes liquids to move convectively upward and downward when a
temperature difference is generated across the surface of a
liquid. So, in order to isolate and study fluid motion caused
by temperature variations along the surfaces of fluids
(thermocapillary motion), it is necessary to escape gravity's
effects.
The interface tension-driven flow where the molecules
of the different liquids interact is a complex process. An
industrial interest in this process developed when
investigators became interested in liquid-encapsulated crystal
growth, where one liquid is processed while enveloped in
another liquid. For example, gallium arsenide, a useful
semiconductor material, has been grown using a liquid
encapsulation technique to keep the arsenide, a toxic
substance, from escaping.
Significance: This experiment will help scientists to better
understand thermocapillary fluid physics. Physicists wanted a
crystal growth furnace where the heating would not create
convective flows, especially time-dependent flows, in the
molten metal. Scientists believe this type of furnace, with
liquid encapsulated electronic melt, could improve crystal
growth in microgravity by reducing or eliminating the
thermocapillary motion in electronic material.
Findings from this experiment will benefit research
in other areas, including environmental science, geology,
advanced aerospace materials development and future space power
systems.
- Environmental scientists are interested in learning
about the interaction between oil and the water it is floating
on. Understanding immiscible fluid flows is of value for
cleaning up environmental water pollution caused by oil spills.
- An interesting geological application will use this
knowledge to study the Earth's mantle. Two convecting,
adjacent layers have an interface that physically behaves in
the same manner. Computer models are used to examine tectonic
movement.
Operations: A special test container was developed for this
experiment and that of Dr. Legros. Three fluids which do not
mix are used to establish two liquid-liquid interfaces in this
three-layer system composed of fluorinert, silicone oil and
fluorinert. Until the experiment is begun on orbit, the three
fluid layers are separated by two metal curtains in the
container. At the initiation of the experiment these curtains
will be retracted. Using temperature variations, fluid motions
are initiated at the two liquid-liquid interfaces, such that
motion at one interface competes with the other. Temperature-
driven flow throughout all three fluid layers will be
visualized using tracers inside the liquid.
Scientists on the ground will observe the behavior of
the interfaces. For example, they will be able to study the
interdependent interactions between the individual layers due
to temperature gradients. These data will be compared with
computer model results and will subsequently help validate the
mathematical models. Findings will provide a better
understanding of the underlying physics involved in these
processes.
Thermocapillary Instability in a Three-Layer System
Experiment Facility: BDPU
Principal Investigator:
Dr. Jean-Claude Legros
Free University of Brussels
Brussels, Belgium
Objective: Surface-tension forces within three layers of
fluids will be studied. The investigator's team wants to learn
how to control fluid flows within the middle layer.
Significance: Understanding these complex types of fluid flows
and finding ways to control them are significant to the field
of material science, particularly the specialized field of
directional solidification. Directional solidification is a
method for growing crystalline materials such as metals and
semiconductors. In this technique, molten material is cooled
so that the boundary between solid and liquid material moves
from one end towards the other during solidification. It is
this boundary region that is particularly significant to
researchers.
Science: This experiment, along with Dr. Koster's
investigation, is expected to provide the first information on
the departure from the rest state of a multi-layer system under
the influence of surface-tension forces. Using these findings,
scientists should be able to devise ways to counteract or
eliminate some of the undesirable effects of surface-tension
forces in space.
The basic mechanisms which cause these types of flows
are understood, but not the means for effectively controlling
them. This type of control becomes highly desirable when, for
instance, researchers want to create flawless silicons and
metals for the electronics industry.
Operations: Experiment procedures will allow scientists to
describe quantitatively the convective pattern arising in three
layers of immiscible liquids, fluorinert, silicone oil, and
fluorinert. The experiment will be conducted in a test
container identical to that used in Dr. Koster's experiment.
Curtains inside the cell, separating the three layers, will be
retracted and heat will be applied. Heating sources above and
below the liquid layers are used to create a temperature
gradient that is perpendicular to the two liquid-liquid
interfaces established between the fluids.
When set temperatures are reached and stabilized,
video and infrared images of the convective motion are
downlinked to investigators on the ground. This phase is
repeated several times with different thermal gradients.
Nucleation, Bubble Growth, Interfacial Micro-Layer,
Evaporation and Condensation Kinetics
Experiment Facility: BDPU
Principal Investigator:
Dr. Johannes Straub
Technical University of Munich
Munich, Germany
Objective: This experiment is designed to provide a better
understanding of boiling processes. It uses vapor bubbles
within a liquid to study the process of evaporation and
condensation at a liquid interface, the point where a liquid
phase of a fluid forms a common surface with its vapor phase.
Science: Evaporation occurs when a liquid changes to a gas due
to increased heat. Condensation is the reverse process, when
the gas cools to a liquid. Scientists will create a small gas
bubble in an evenly heated, liquid refrigerant. The bubble
will become larger as it draws heat from the liquid, until the
temperatures of the liquid and gas reach a state of
equilibrium.
Scientists will study physical changes during
evaporation and condensation at the interface where the bubble
contacts the liquid. In Earth's gravity, bubbles disappear
very rapidly from the field of view, hindering such studies.
In microgravity, the vapor bubble will remain where it is
formed and grow in size, making it easier to observe.
Significance: Evaporation and condensation at liquid-gas
interfaces are fundamental processes in our lakes, seas and
rivers. The processes also have technical applications in
heat exchangers, energy conservation systems and the chemical
industry. A precise knowledge of the kinetics, or energy
processes, which govern boiling, is important to understanding
environmental effects and improving technical systems.
Background: The science team has conducted this experiment in
the brief weightless conditions available during parabolic
flights with a specialized Caravelle aircraft, a drop tower and
a sounding rocket flight. However, this will be its first time
in orbit.
Operations: A crew member will place a sealed aluminum
container filled with Freon into the Bubble, Drop and Particle
Unit. Heaters within the container will warm the refrigerant
evenly from all sides. A compressor will increase pressure in
the container to remove any air bubbles which may exist in the
liquid, then reduce pressure so the liquid will reach a
supersaturated state, where it remains liquid at a temperature
above that at which it would normally become a gas.
Then, experiment scientists on the ground will
command a short heat pulse from a spot heater, which will
create a gas bubble inside the liquid. The bubble will draw
heat from the supersaturated liquid and continue to expand
until the gas and liquid reach equilibrium. Cameras and
sensors will observe and record temperature, Freon density, and
positions of the bubble. After each phase of the experiment,
controllers will increase the pressure to condense the bubble.
They will repeat the experiment at six different heat
levels, between room temperature and approximately 185 degrees
Fahrenheit (85 !C).
Static and Dynamic Behavior of Liquid in Corners, Edges and
Containers
Experiment Facility: Bubble, Drop and Particle Unit
Principal Investigator:
Dr. Dieter Langbein
ZARM Institute
Bremen, Germany
Objective: This experiment will record the behavior in
microgravity of liquid surfaces, making precise measurements of
the angles where liquids and solid surfaces meet.
Science: In a weightless environment, liquid movements due to
gravity are minimized, allowing for observations of more subtle
fluid dynamics, such as thermocapillary flows. This type of
liquid movement becomes the main mechanism of heat transfer
within fluids. During IML-2, this fluid investigation will
confirm the existence and stability limits of liquid surfaces
in a cylinder.
Significance: This experiment will give scientists insight
into the wetting phenomena caused by capillary forces. The
data collected during this experiment will also help design
better surface-tension tanks (tanks that provide fuel at the
outlet valve via capillary effects alone, without relying on
gravity or pistons).
Equipment and Operation: Silica Matched Liquid Cargille 50350,
a liquid which has the same refractive index as quartz, will be
injected into the quartz test cell of the Bubble, Drop and
Particle Unit. This test cell, which contains four different
transparent, polygonal cavities with different wall angles,
will be maintained between 68 and 175 degrees Fahrenheit (20
and 80 degrees Celsius), using heaters situated between each
cell. The surface shapes produced as the temperature and
liquid volumes are changed will be observed using background
and cross-section illumination.
Background: IML-2 is the first on-orbit flight for this
experiment. Previously, this investigation was conducted from
sounding rockets launched in Sweden and inside a drop tower in
Germany.
Critical Point Facility
Developed by: European Space Agency (ESA)
European Space Research and Technology Center
(ESTEC) Noordwijk, The Netherlands
Objective: Several experiments will be able to measure and
visually record special fluid properties at their "critical
point" with the Critical Point Facility, developed by the
European Space Agency.
At the critical point, a fluid is neither a gas nor a
liquid, it is both; more precisely, the material fluctuates
back and forth in small volumes from one state to another so
that the state of the total volume is indistinguishable.
Scientists have been unable to study this interesting behavior
closely in normal gravity.
In Earth's gravity, critical point experiments are
difficult to perform due to the fluid being very compressible.
Most of the sample cannot be maintained at the critical density
because the fluid's own weight compresses part of the sample to
a density greater than the critical density. The most critical
region literally collapses under the weight of the fluid.
Significance: Critical point phenomena are common to many
different materials. Understanding how matter behaves at the
critical point can provide insight into a variety of physics
problems ranging from phase changes in fluids to magnetization
changes in solids.
Information gathered from these experiments refines
the physical theories that describe the mechanism and the rate
of change of fluid states.
Background: On Earth, gravity blocks experimental efforts in
working with pure fluid critical-point systems. The feverish
experimental activity of the 1960s and 1970s in critical
phenomena slowed in the 1980s partly because of gravitational
limitations on the acquisition of experimental data closer to
the critical temperature. However, some unexpected
observations of near-critical fluids in low gravity have
encouraged the study of equilibration dynamics with new
enthusiasm in critical phenomena research.
Hardware Description: The facility is a multi-user system
capable of accommodating the experiments of several researchers
sequentially in any one mission. Interchangeable thermostats
for controlling the temperature of an experimental sample are
inserted in the facility, where they are surrounded by an
optical diagnostics system to monitor the phenomena of
interest.
Temperature is extremely important in critical point
experiments. So, the facility was designed to provide
extremely accurate thermal control of the test fluid.
The CPF hardware is composed of two interconnected
drawers: the electronics and the experiment drawers.
The front panel of the electronics drawer allows the
crew to manipulate the experiment via an alphanumeric key pad
display, switches and lamps.
The experiment drawer contains a front panel access
door through which different experiment thermostats can be
inserted for processing.
A black and white video camera is a useful tool in
the apparatus. This camera is used to monitor fluid dynamics
of the sample when it undergoes temperature cycling during an
experiment. A 35mm camera is attached to the front of the
experiment drawer for still photos. A laser and a light
emitting diode, which serve as light sources for the experiment
also are located inside the drawer.
The facility will measure density fluctuations near
the critical point through the use of laser light scattering
and interferometry. Interferometry splits and subsequently
reunites beams of light after they travel different paths. The
two separated beams interact (interfere) with each other in
such a way as to allow precise measurement of very small
distances and thicknesses. These data show the local fluid
density changes in various parts of the cell.
Operations: The sample fluid held near its critical density is
housed within sealed cells. The cells are installed in a high
precision thermostat which holds them at a temperature between
86 and 140 degrees Fahrenheit (30 and 60 degrees Celsius). As
the sample approaches its critical pressure and temperature
from above, the normally clear gas becomes opalescent (cloudy)
as it passes through the critical point. On Earth, this change
takes place within a matter of seconds. In microgravity, the
change happens uniformly over minutes, permitting scientists to
gather large amounts of data.
Unusual density fluctuations occur at the critical
point. These fluctuations strongly scatter the light and reduce
its intensity. Detectors measure these variations. After the
critical point has been crossed, these fluctuations diminish,
and the sample forms patches of either liquid or gas phases.
Intermittent television video is available to
investigators on the ground. Operators also gather nearly
full-time digitized video snapshots at six-second intervals of
the phenomena in progress. Once activated on orbit, the
facility can operate in a fully automatic mode. Experiments
are then conducted according to a prerecorded timeline. During
the mission, however, the investigator's team can send remote
commands to modify their experiments in real-time after
analyzing optical, thermal and pressure data received at
Spacelab Mission Operations in Huntsville, Ala. More than
1,100 such commands were sent successfully during the first
flight of the CPF on IML-1, during some 120 hours of continuous
operation.
The Piston Effect
Experiment Facility: CPF
Principal Investigator:
Dr. Daniel Beysens
CEA Department of Condensed Matter Physics
Gif sur Yvette, France
Objective: This investigation explores a specialized field
within fluid physics. A hot layer within a contained volume of
fluid is generated and expands and heats the rest of the fluid
in a way somewhat similar to compressing it with a piston.
This unique phenomenon by which a particular temperature can
become uniformly distributed throughout a container of fluid
has been given the name, the "piston effect". The effect
arises only in fluids when they are at or near their critical
point, and therefore highly compressible, or elastic. Such
highly compressible fluids can be easily compressed into a
given amount of space. One result is that they are very
sensitive to thermodynamic effects.
As part of this experiment, the principal
investigator's team is interested in what will happen to the
pressure within the sample cell during two Space Shuttle
maneuvers, which submit the test cell and fluid to a weak,
controlled acceleration.
Science: When a substance is brought to its critical point
condition and then heated beyond it, it has unique
characteristics for a fluid and is said to be "supercritical."
In this condition, one attribute of the substance is unusually
high compressibility, or elasticity. A related property is
that the fluid can exhibit very rapid transmission of heat
through a type of flow similar to convection, but not caused by
gravity. In fact, this type of transmission appears somewhat
similar to the way sound waves travel through a fluid.
For a small fluid container, this piston effect form
of heat transport occurs at a typical time range of between a
hundreth of a second and 30-50 seconds, depending on the
temperature relative to the fluid's critical temperature. This
can be compared to "acoustic time," based on the velocity of
sound -- which is in the range of only a few microseconds --
and "diffusion time," which is on the order of hours or even
days for a substance near its critical temperature. The
typical time for the piston effect is much longer than acoustic
time, but shorter than diffusion time. It is a significant
property because this is the time at which thermalization
occurs. Thermalization, the process of a local temperature
change becoming uniformly distributed, for a supercritical
fluid occurs at the typical time for this piston effect.
Significance: This research has potential to help us
understand the effective management of fluids used in fuel
cells and rocket propulsion tanks.
Another expanding field of study uses supercritical
fluids in industrial extraction processes, because the
supercritical fluids are remarkable solvents.
Background: Recent numerical simulations and experiments on
sounding rockets, the first Spacelab International Microgravity
Laboratory mission, and the MIR space station have demonstrated
the existence of the thermocompressible transport of heat, but
scientists still know very little about the characteristics of
this effect.
Operations: A number of experiments will be performed to
determine the temperature, density, and pressure evolution
using a temperature sensor or a laser beam as a local heat
source. For this experiment, two fluid samples in the same
thermostat will be studied simultaneously over a 43-hour
period.
Thermal Equilibration in a One-Component Fluid
Experiment Facility: Critical Point Facility
Principal Investigator:
Dr. Richard A. Ferrell
University of Maryland
College Park, Md.
Objective: This experiment is designed to study the critical-
point properties of a fluid composed of identical molecules.
At the critical temperature, there is no distinction between
the liquid and the gas. The two phases become
indistinguishable.
During these phase changes, energy is received and
released by either heat diffusion or subjecting the substance
to pressure changes -- a form of work. Heat diffusion occurs
very slowly near the critical point, while pressure changes
(the mechanism of imposed work) happen rapidly within the
fluid. Studying how these two energy-transfer mechanisms
interact is the goal of this experiment.
Significance: While it is of fundamental scientific
importance, this experiment will also provide results of
importance to other low-gravity, critical-point experiments now
under development. In order for researchers to plan the
timelines for these experiments, it is necessary to determine
how quickly their test samples will reach thermal equilibrium
after temperature step changes near the critical point.
Science: Any pure fluid possesses a liquid-vapor critical
point where liquid and vapor are no longer distinguishable.
The fluid also is highly compressible. This compressibility is
the root of difficulties posed by gravity, when attempting to
study critical point phenomena. At a given temperature, the
critical zone is too small on Earth to measure. But the
absence of gravity reduces the weight of the fluid on itself
and widens the critical zone for a given temperature, allowing
scientists to maintain critical point conditions over a large
enough region to allow studying the critical behavior in
detail.
Background: The first thermal equilibration experiment flew on
the first International Microgravity Laboratory mission in
1992.
Operations: The investigation has two experiments, each made
up of two parts. One experiment is called "thermal
equilibration-B." It studies thermal transmission by the
diffusion process, by setting up a steady heat flow across the
cell, using a small heater attached to one side.
Interferometry and light scattering will again be used to track
the time evolution of density and temperature.
The second, "adiabatic fast equilibration," studies
how "pressure work" transports energy from one part of the test
cell to another. Temperature changes will be induced both
externally, by changing the temperature of the confining
windows, and internally, by heat from a pulse of current
passing through a resistance wire inside the cell.
When the wire is charged to a static potential of up
to 500 volts, the sulfur-hexafluoride in the cell is pulled
into the electric field around the wire, causing a local
density change observable by an optical technique known as
interferometry. The electric field allows for fast change of
cell conditions without heat input. This is a unique way to
study diffusion in non-critical fluids.
This investigation will be conducted with the fluid
sulphur-hexafluoride. The thermostat for each experiment will
hold two fluid cells with a layer of fluid about a sixteenth of
an inch thick (1 or 2 mm) confined between transparent windows
at the proper critical density. One cell will be for
interferometry measurements and the other for visualization.
The response of the fluid in both thermostats will be
monitored visually with a video camera as well as by
interferometry and light scattering. Interferometry gives
information on the local fluid density changes in various parts
of the cells. Light scattering becomes more intense near the
critical point. Therefore, it is a sensitive measure of
temperature changes.
Density Equilibration Time Scale
Experiment Facility: CPF
Principal Investigator:
Dr. Hermann Klein
DLR Institute for Space Simulation
Cologne, Germany
Objective: The experiment is aimed at improved understanding
of mechanisms by which heat flow and density stabilization
occur in a fluid substance, particularly close to its critical
point.
Science: Subjecting a fluid substance to any change, for
instance a tiny addition of heat, results in effects such as
the introduction of localized density variations. Assuming the
system was previously in a stable state, this amounts to a
temporary disruption, or imbalanced state. Then, a relaxation
or smoothing-out process will occur as the localized
differences dissolve and conditions adjust toward uniformity
throughout the fluid. Scientists refer to such a process,
which ends with the substance at stable conditions, as
"equilibration." They are particularly interested in the
detailed physical mechanisms by which such changes occur --
mechanisms which include thermal transport, or how heat is
moved, and mass transport, or how matter is rearranged.
As an example of such a process, a fluid which is
below its critical temperature consists of distinct gas and
liquid phases. One can see a boundary, or meniscus, between
the two. However, heating of the fluid -- causing it to pass
through its critical temperature -- causes this visible
boundary to disappear. The fluid has entered a new single-
phase condition where the liquid and gas are indistinguishable.
When conditions such as density and temperature have stabilized
following the phase-change process, the fluid is homogeneous.
Local imbalances will be present and the system will be in a
non-equilibrium state until mass transport is able to achieve a
balance among the areas of density in homogeneity. It takes
time for the stabilization to occur; this time element is of
particular interest to physicists.
An analogous situation occurs when a fluid sample is
cooled from above to below the critical point. It starts as a
single fluid phase and becomes separate, coexisting phases of
gas and liquid with a distinguishable boundary between the two.
However, it again takes time before the equilibrium densities
of the two phases have become fully developed, and while this
is going on, there is an associated redistribution of mass
under way, or rearrangement of matter within the fluid.
Significance: The study of fluid systems is a fundamental area
of physics and one of the key objectives in the fluid systems
field is understanding of equilibration processes and times.
Equilibration times are very significant for obtaining
meaningful experimental results in the measurement of physical
properties. Near the critical point, physical properties take
on a remarkable nonlinear character, something which can only
be fully assessed when equilibrium states and equilibration
processes are thoroughly known.
This research is also expected to provide a better
understanding of the behavior of fluids in rocket and
spacecraft thruster reservoirs, of processes inside heat
exchangers, and of cleaning methods involving fluids at high
pressure.
Operations: Sulphur hexafluoride is also the sample fluid for
this experiment, because it is chemically inert and reaches its
critical point at moderate conditions. During experiment runs,
the sample is subjected to precisely controlled changes of
temperature, to produce subtle physical effects such as
described above. In the Critical Point Facility, a laser beam
is directed through the sample. The amount to which the light
intensity diminishes after passing through the sample -- the
degree of light attenuation -- is an indicator of how close the
sample is to the actual critical point, and also permits
observing the progressive stages from disequilibrium to
equilibrium and vice versa.
Crew involvement in the experiment consists primarily
of unstowing and installing the dedicated experiment thermostat
and powering up the laser and camera systems early in the
mission. They will perform specific steps to initiate the
experiment and verify that data is being properly gathered.
After that, a combination of programmed commands and ground
control inputs are used to cycle the sample through experiment
runs.
Heat Transport and Density Fluctuations in a Critical Fluid
Experiment Facility: CPF
Principal Investigator:
Dr. Antonius Michels
University of Amsterdam
Amsterdam, The Netherlands
Objective: This experiment will measure the propagation of
heat within a fluid near its critical point.
Science: Fluids reach their critical point when a precise
combination of temperature and pressure compels their liquid
and gas phases to become identical and form one phase. In this
unusual state, the properties of the fluids can be altered
dramatically.
One process of interest to scientists is how heat is
transported within a critical fluid. There are three
fundamental mechanisms which transport heat: propagation of
sound, thermal diffusion and adiabatic compression heating,
which is heating where there is negligible external input or
release of heat. The latter two mechanisms are the focus of
this experiment.
With liquids and gases, thermal diffusion is
predominant. However, it becomes slower and slower as the
fluid nears its critical point. Since fluid becomes
increasingly compressible as it approaches the critical point,
the compression heating becomes dominant in the near-critical
state.
On Earth, heat transport investigations are flawed by
gravity-driven convection. This space-based experiment allows
scientists to study the relative importance of thermal
diffusion and adiabatic compression heating in a convection-
free environment.
Significance: Critical fluids are useful in technical
applications such as extraction processes, where materials are
transferred from low density to high density with very little
force. Manufacturers must accurately calculate the feasibility
of the technique for their specific process. If they are only
a few percentage points off in these calculations, the process
could be too expensive or inefficient to be practical. A
better understanding of how heat transport mechanisms are
altered near the critical point is important to improve the
accuracy of these calculations.
Knowledge gained from this experiment will also
improve scientific understanding of fundamental fluid physics.
Operations: A sealed canister containing sulfur hexafluoride
will be placed in the Critical Point Facility by a crew member.
Pre-programmed computer commands will begin the search for the
critical point, which will be achieved at a temperature between
113 and 115 degrees Fahrenheit (45 and 46 !C). The sample will
be heated to about three degrees higher than the critical
temperature, then it will be lowered step by step Q two thirds
of the difference, then two-thirds again, until the critical
point is reached.
The experiment team will monitor density differences
within the fluid via downlinked video images as the critical
point is crossed several times. Motion of the density
differences, along with readings from temperature sensors
within the sample container, will tell them how heat is being
transported. A remote team in Amsterdam will receive
simultaneous video and data, which they will process for more
accurate understanding of the experiment.
Background: Dr. Michels performed a different experiment in
the Critical Point Facility during the 1992 IML-1 mission. It
helped confirm the effectiveness of the experiment facility for
space-based investigations.
Vibration Isolation Box Experiment System (VIBES)
Payload Developer: NASDA
Objective: The Vibration Isolation Box Experiment investigates
the effects of so-called "g-jitter," disturbances caused by
crew movement and experiment equipment operations in space
laboratories such as Spacelab. The information will be useful
for experiment systems sensitive to the quality of the
microgravity environment.
The experiment will test the effectiveness of a box
designed to isolate sensitive experiments from vibrations
caused by g-jitter.
Significance: The IML-2 mission has been designed especially
to provide the highest quality microgravity environment
available in the Space Shuttle. However, it is impossible to
totally eliminate all disturbances to such an environment.
Crew movements, equipment operations and occasional thruster
firings can disrupt the quiet low-gravity environment and may
affect some science experiments.
The Vibration Isolation Box Experiment System will
support two experiments to study how g-jitter affects natural
fluid flows, diffusion and thermally driven fluid flows under
microgravity.
Both experiments will be performed with and without a
damping system, to see how well the isolation box counteracts
the effects of g-jitter on sensitive microgravity experiments.
Experiment Hardware and Operations: This system consists of a
lockable vibration isolation box, two experiment units and an
acceleration measurement unit.
Experiment units are placed inside the vibration
isolation box inner container. The container is attached to an
outer frame by a visco-elastic damping material. When the
damping system is enabled, it should isolate experiments inside
the box from some of the movements which would otherwise
disturb them. Windows in the experiment units and the
isolation box allow experiment operations to be videotaped.
The system has an acceleration measurement feature,
consisting of two accelerometer sensor heads and a recording
apparatus. One is mounted within the isolation box inner
container, and another is mounted in the system's exterior
framework, allowing accelerations to be measured both inside
and outside the isolation box. After the mission, scientists
can compare the acceleration measurements with fluid movement
recorded on videotape.
Background: This experiment system is provided by the National
Space Development Agency of Japan. A similar system was flown
as an avian egg container in Spacelab-J to protect the egg
from launch vibration.
Influence of G-Jitter on Natural Convection and
Diffusive Transport
Experiment Facility: VIBES
Principal Investigator:
Dr. Hisao Azuma
National Aerospace Laboratory
Chohu-shi, Japan
Objective: This experiment will measure the effects of
disturbances on flow and diffusion in a liquid within the
Shuttle. It also will study the ability of the Vibration
Isolation Box Experiment System to isolate experiments from
these disturbances.
Significance: Disturbances caused by crew movement and
equipment operations, known as g-jitter, can interrupt the
quiet microgravity environment needed for some space
experiments. In most cases, these disturbances are
unavoidable. Experience from previous missions has proved the
value of having astronauts onboard a space laboratory to
operate, observe and adjust experiments. Essential equipment
operations, from the hum of experiment systems to the motion of
the TV antenna that transmits signals to ground controllers,
create disturbances as well.
This experiment will determine how much g-jitter
influences natural convection and diffusion in a liquid, as it
is heated from one side to create a fluid flow. The experiment
will be performed with and without the isolation box damping
system, to test how well the system counteracts g-jitter
effects.
Operations: A crew member will set up the convection and
diffusion unit inside the isolation box during a time when all
seven astronauts are awake and active. The unit is a
rectangular container filled with diluted salt water that
includes indicator dye. Both the isolation box and experiment
unit have observation windows.
One side of the container will be heated to create a
temperature difference in the water. Flows caused by residual
gravity in the Shuttle and g-jitter can be tracked by observing
the colored dye, and live video of the fluid motion will be
transmitted to ground controllers. The experiment then will be
repeated with the isolation box suspended from the facility's
outer frame with a visco-elastic damper. Scientists will
evaluate how much the damping system protects the experiment
from external disturbances.
The system's acceleration measurement system will
record motion detected by its sensors for later comparison with
the video.
Study on Thermally Driven Flow Under Microgravity
Experiment Facility: VIBES
Principal Investigator:
Dr. Masao Furukawa
NASDA Tsukuba Space Center
Ibaraki, Japan
Objective: This experiment studies the basis for a more
efficient spacecraft thermal management system. It is planned
to confirm the basic function of liquid transport mechanisms in
space using the principle of differential vapor pressure.
Science: One method for managing excess heat is a two-phase
fluid loop, which transports liquid that separates from the co-
existing vapor in microgravity. This experiment will test the
fluid-transporting characteristics of a device known as an
accumulator Q comparing its performance with and without a
mechanism designed to damp, or check, vibrations created by
motion within the spacecraft.
Two vessels inside the accumulator contain water and
are joined by a small channel. Water in one vessel will be
heated, and vapor pressure differences between the two chambers
will cause the liquid to move toward the other side.
On Earth, the system works well because water vapor
rises to the top of the heated chamber, displacing some of the
water to the other side. In microgravity, however, factors
masked by gravity on Earth like the tension on the surface of
the fluid will play a significant role in separating the fluid
flow.
Significance: The next generation of spacecraft will be
larger, more complex to operate, and will generate more heat.
Therefore, their thermal management systems must have greater
heat acquisition and rejection capability and be able to
transport waste heat over a long distance. This study helps
develop fluid management technologies such as gas and liquid
separation, liquid reorientation, or liquid transport.
Experiment scientists consider it indispensable for developing
a two-phase fluid loop system, considered to be a primary
candidate for future spacecraft thermal management.
Results also will contribute to the design of fuel
cells, power plants, and environmental and life support systems
which require thermal management of liquids.
Operations: A crew member will place the accumulator inside
the Vibration Isolation Box, then heat the fluid on one side to
observe the transfer process.
One experiment run will be completed without the
isolation box damping mechanism engaged. For the other run,
the isolation box will be suspended from the facility's outer
frame with a visco-elastic damper. Behavior of the liquid flow
and two-dimensional vapor/liquid diffusion will be recorded on
video during both runs. Scientists evaluate how much the
damping system protects the experiment from external
disturbances.
The system's accelerometer will record motion
detected by its sensors for later comparison with the video.
Space Acceleration Measurement System (SAMS)
Payload Developer: NASA
Principal Investigator:
Mr. Charles Baugher
NASA Marshall Space Flight Center
Huntsville, Ala.
Objective: The Space Acceleration Measurement System (SAMS)
instrument will monitor and record higher-frequency onboard
accelerations and vibrations experienced in the Spacelab module
during flight. After the mission, scientists for IML-2
microgravity investigations will compare these records with
their own data to identify accelerations which may have
influenced their experiments.
Significance: Many of the IML-2 experiments require a very
smooth ride through space so their delicate operations will not
be disturbed. To maintain the most stable environment
possible, the Shuttle will fly most of the mission with its
tail toward Earth. In this orientation, called a gravity-
gradient attitude, the vehicle's position is maintained
primarily by natural forces, reducing the number of orbiter
thruster firings which disturb acceleration-sensitive
experiments.
Even in a gravity-gradient attitude, though,
accelerations caused by crew movements, equipment operations
and occasional thruster firings can temporarily disrupt the
quiet low-gravity environment and may affect microgravity
science experiments.
Different kinds of disturbances show up at different
frequencies. They are measured in terms of fractions of
Earth's gravity. Accelerations at one frequency may interrupt
one type of experiment but have no effect on others. By
studying SAMS data, scientists can determine not only that a
disturbance occurred but can be fairly certain what caused it.
They can then make allowances for the disturbance as they
analyze their experiment results.
Scientists' growing understanding of how various
accelerations affect individual experiments is helping
researchers improve equipment and procedures for future flights
on the Shuttle and for Space Station operations.
Experiment Hardware and Operations: Three remote sensor heads,
each measuring motion in three dimensions, are located near
selected experiments within the Spacelab module. They measure
accelerations as small as one-millionth of Earth's gravity.
The signals are transmitted via cable links to a central
control unit in the center aisle of the module, where they are
amplified, filtered and converted to digital data for storage
on optical disks. Each disk can store up to 400 million bytes
of data.
The sensor located near the Bubble, Drop and Particle
Unit measures frequencies in the range of 10 Hertz, the sensor
next to the Critical Point Facility measures frequencies of
about 5 Hertz, and the one near the Electromagnetic
Containerless Processing Facility measures frequencies in the
100 Hertz range. These materials and fluids science
experiments are particularly sensitive to the frequency ranges
SAMS will record.
The crew will activate the SAMS experiment halfway
through Flight Day 1, then change out optical disks daily as
they are filled. The experiment operates continuously for the
duration of the mission.
Background: Prior to IML-2, the Space Acceleration Measurement
System flew on nine Shuttle missions, including IML-1 in
January 1992. In addition to the information SAMS provides for
other experiments, NASA has used its data to better understand
the microgravity environment in different areas of the Shuttle.
The instrument is provided by NASA's Lewis Research Center in
Cleveland, Ohio.
Quasi-Steady Acceleration Measurement (QSAM)
Payload Developer: German Aerospace Research Establishment
(DLR)
Principal Investigator:
Dr. Hans Hamacher
DLR Institute for Space Simulation
Cologne, Germany
Objective: The Quasi-Steady Acceleration Measurement (QSAM)
experiment is primarily designed to detect steady, very low-
frequency, residual accelerations between 0 and 0.02 Hertz.
These disturbances to the Spacelab microgravity environment
include tidal accelerations caused by variations in Earth's
gravitational field, atmospheric drag, and the slow rotation of
the orbiter necessary to maintain its orientation toward the
Earth.
Significance: This experiment, along with the Space
Acceleration Measurement System, will provide the IML-2 mission
with the most effective acceleration measurement systems.
Nearly all the IML-2 experiments rely on the state of
microgravity -- commonly known as weightlessness -- to
accomplish their goals. However, various disturbances exist in
a spacecraft which make it impossible to achieve complete zero-
gravity conditions. These include rapidly changing movements,
like those of the crew or periodic equipment operations; and
steady accelerations such as the slight pull on the Shuttle
created by atmospheric drag.
All experiments can tolerate a certain level of
disturbance. But different experiments are sensitive to
different types of accelerations. Scientists need to know the
exact level of accelerations that occur during their
experiments to correctly interpret their results. In the past,
the whole range of accelerations could not be covered by one
system. QSAM will fill in the gaps by measuring steady, low-
frequency accelerations, which affect some physical processes
more than higher frequency accelerations.
Experiment Hardware and Operations: This experiment uses four
rotating sensor heads and three stationary sensors to measure
residual quasi-steady accelerations. The stationary sensors
record accelerations of up to 50 Hertz. To achieve reliable
measurements in lower frequencies, the accuracy of the sensors
must be tested, or calibrated, in orbit. The rotating sensors
measure accelerations in one axis, then flip 180 degrees and
measure them in another, ensuring the accuracy of the readings.
They should be able to sense disturbances as small as one ten-
millionth of Earth's gravity (10 -7), ten times more still
than theoretical "microgravity" (10 -6).
Measurements will be recorded throughout the mission
on optical disks. The crew will activate the experiment about
12 hours after launch and change out disks approximately once
every two days. Otherwise, the experiment operates
autonomously.
Background: IML-2 is the first flight for this experiment, and
one of the first which will take measurements of steady, very
low frequency residual accelerations. The Quasi-Steady
Acceleration Measurement system was developed by the German
Aerospace Research Establishment (DLR).
Biostack (BSK)
Payload Developer: DLR
Principal Investigator:
Dr. Guenther Reitz
DLR Institute for Aerospace Medicine
Cologne, Germany
Objective: Biostack is part of a multinational program to
determine the impact of high atomic number, high-energy cosmic
radiation particles on life in space. It uses radiation
detectors enclosed between a variety of biological specimens to
monitor particles entering the Spacelab module. The specimens
will be studied post flight to locate the path and entry point
of each heavy ion in the biological layer, and determine the
extent of any changes or damage it may have caused to the
organism.
Significance: Orbiting spacecraft operate in a complex
environment of electromagnetic radiation, charged particles
from solar and galactic radiation, and charged particles
created by the interaction of galactic radiation with Earth's
atmosphere. Previous experiments indicate that particles of
high atomic number and high energy have potentially serious
side effects on living organisms. These effects cannot be
fully investigated on Earth, because the atmosphere filters out
most of this radiation. Biostack will help scientists
understand the importance, effect and hazard of these high-
energy particles on various living organisms in space. This is
important to development of space radiation forecasting systems
which may be needed for longer space flights.
Experiment Hardware and Operations: Three sealed aluminum
Biostack containers are mounted in a Spacelab rack. Inside the
containers, layers of different biological specimens are placed
between different types of detectors to measure incoming
radiation. When cosmic particles pass through the Biostack,
they deposit their high energies in the layers of radiation
detectors and specimens. This allows scientists to locate the
trajectory of each heavy ion in the biological layer and to
identify the site of penetration inside the biological subject.
The experiment uses two different strains of shrimp
eggs and salad seeds. After the mission, scientists compare
any damage to the specimens with cosmic particle penetrations
identified by the detectors. This helps them assess how
specific amounts of radiation affect different types of life.
The experiment, which is entirely passive, will
collect particles throughout the mission.
Background: Biostack has a long history in the space program.
Similar instruments flew in the 1970s on Apollo 16 and 17 and
the Apollo-Soyuz Test Project. This experiment, developed by
the German Aerospace Research Establishment (DLR), has flown
previously on three Spacelab missions: Spacelab 1 in 1983,
Spacelab-D1 in 1985, and IML-1 in 1992. Results from the early
missions demonstrated that high-energy particles can have
serious biological effects on an organism, since complete cells
can be damaged or destroyed. The ultimate consequences of such
damage depend on the organism's ability to repair or replace
the affected cell.
Extended Duration Orbiter Medical Project (EDOMP)
Payload Developer: NASA
Objective: The Extended Duration Orbiter Medical Project is
designed to protect the health and safety of the crew during
12- to 17-day missions aboard the Space Shuttle. The series of
investigations is designed to assess the medical status of the
crew members and the environment in which they work.
Significance: As Space Shuttle missions become longer and as
plans are made for extended stays aboard Space Station, it is
essential to both understand the effects of weightlessness and
radiation on space travelers and develop measures to protect
them from harm.
Background: This medical project was developed by NASA's
Johnson Space Center for missions where Extended Duration
Orbiter equipment allows Shuttle flights to increase from the
7-to-10-day range to the 13-to 16-day flights.
The project is an umbrella designation for various
activities designed to assess or protect crew health during
long missions. Though elements of the project were included on
earlier missions, it flew as a separate payload aboard the
USML-1 Spacelab in 1992. IML-2 will be its second flight as a
Spacelab payload.
For IML-2, the Extended Duration Orbiter Medical
Project includes two experiments. The Lower Body Negative
Pressure apparatus continues evaluation of a treatment to
counteract orthostatic intolerance, the dizziness astronauts
can experience as blood pools in their legs on return to
gravity. The Microbial Air Sample tests air in the Spacelab
and crew cabin for accumulations of airborne bacteria and fungi
which may cause human illnesses.
Lower Body Negative Pressure
Experiment Group: EDOMP
Principal Investigator:
Dr. John Charles
NASA Johnson Space Center
Houston, Texas
Objective: The Lower Body Negative Pressure (LBNP) experiment
evaluates the effectiveness of a treatment designed to
counteract orthostatic intolerance, the "lightheadedness"
astronauts sometimes experience when returning to Earth from
space.
Significance: Without the force of gravity, astronauts' body
fluids shift toward their heads and upper torsos. This shift
is associated with other changes, such as fluid volume loss and
altered control of cardiovascular functions. When space
travelers return to Earth and "normal" gravity, body fluids are
pulled back to the legs. Sometimes this creates a reduced
blood flow to the brain when they stand up. In extreme cases,
it could cause loss of consciousness. Treatments to counteract
these effects protect the long-term health of the crew and
ensure they will be alert for critical landing operations.
Background: LBNP was used on Skylab in 1973-4 to monitor loss
of orthostatic tolerance in astronauts who spent up to 84 days
in space. The current LBNP equipment first flew on STS-32 in
1990 as an independent payload. IML-2 will be its ninth
flight.
Results from previous flights indicate that
orthostatic intolerance can be countered by ingesting salt
tablets and water while exposing the lower body to four hours
of reduced pressure. This combined treatment has been shown to
recondition the cardiovascular system for up to 24 hours.
Spacelab-J tests on female astronauts indicated it is as
effective on women as men, contrary to predictions based on
bed-rest studies on the ground.
Operations: The primary equipment for the LBNP activity is a
fabric bag in which a partial vacuum can be created. It
encases the astronaut's lower body and seals at the waist. By
slightly lowering the pressure within the bag, body fluids are
drawn back to the lower extremities, mimicking the natural
fluid distribution that occurs when a person stands up on
Earth. This conditions the cardiovascular system to accept the
ingested salt and water for reentry and improves orthostatic
tolerance.
Two different procedures are conducted in the
experiment. Four times during the flight, the LBNP device will
be used to monitor the adaptation to space flight by Payload
Specialist Chiaki Mukai and Payload Commander Rick Hieb. In
these 45-minute "ramp" tests, the LBNP is gradually lowered and
raised again. Measurements will be made of heart size and
function by ultrasound cardiology, blood pressure and heart
rate. Leg circumference will be measured before and after the
sessions to determine the volume of blood in the lower body.
The day before landing, Hieb and Mukai will spend
four hours with their lower body encased in the low-pressure
bag. During the first hour of this "soak" treatment, they will
drink water and take salt tablets. This combined treatment
will pull fluids back into the lower body where they should
remain for up to 24 hours. Scientists will evaluate the
success of the treatment by examining cardiovascular data taken
on Hieb and Mukai shortly after landing.
Microbial Air Sampler
Experiment Group: EDOMP
Principal Investigator:
Mr. Duane L. Pierson
NASA Johnson Space Center
Houston, Texas
Objective: The Microbial Air Sampler collects information on
airborne contaminant levels in the Shuttle throughout the
mission. Results from IML-2 will be added to data from
previous flights to establish baseline microbial levels during
missions of different lengths and to evaluate potential risks
to crew health and safety.
Significance: Because certain microorganisms can cause
allergic reactions or infections, maintaining acceptable air
quality in "tight buildings" with little or no outdoor air is
important to protect the health of people who inhabit those
buildings. Spacecraft are the ultimate tight buildings,
because the air supply is completely contained within the
vehicle. In addition, particles that normally settle down onto
the ground or other surfaces on Earth remain airborne in space.
Measurements of air quality taken before and after
brief Shuttle missions suggest that inflight microbial levels
are typical of those from crowded indoor environments. In the
closed environment of the Shuttle, however, bacteria levels
gradually increase during flight. This is not unexpected,
since the Shuttle's air-handling system was not designed to
remove airborne organisms.
If results show that levels of microorganisms
increase during relatively long Shuttle missions to the point
of becoming a concern, recommendations will be made to counter
these effects with additional air-filtration devices.
Background: The Microbial Air Sampler first flew on the
Spacelab Life Sciences-1 mission in 1991. IML-2 will be its
eleventh flight.
Results from previous missions indicate that the low
relative humidity in the Spacelab tends to reduce fungal
propagation. Bacteria identified were those commonly
associated with the human body, and the number tended to rise
and then fall by the end of the mission. However, data
collection on long-term missions is considered insufficient at
this point to predict whether another rise in microbial
particles may occur later in a long flight.
Operations: This experiment uses a hand-held, battery-powered
air sampler. Air is pulled into the sampler by a motorized
fan. Particles in the air are trapped within the device on
plastic strips containing agar, a gelatinous material used to
culture bacteria.
Crew members will insert an agar strip into the
sampler, expose it to the surrounding air for two minutes to
collect bacteria samples, then store the strip in a plastic bag
for analysis back on Earth. They then will repeat the process
with another strip, treated with a different solution to
attract fungi microbes.
Astronauts will collect air samples from selected
areas of the Spacelab, flight deck, or middeck near the
beginning, middle and end of the flight. This procedure allows
the number and type of airborne microorganisms to be identified
over a relatively long Shuttle mission.
Slow Rotating Centrifuge Microscope
Niedergeschwindigkeits-Zentrifugen-Mikroskop (NIZEMI)
Payload Developer: German Space Agency (DARA)
Objective: The Slow Rotating Centrifuge Microscope, NIZEMI,
facility will provide scientists with the capability to observe
both living and non-living matter exposed to levels of gravity
ranging from 10-3 g (one thousandth of Earth's gravity) to 1.5
g. Free from Earth's gravitational pull, investigators will be
able to see how organisms react to different gravity levels,
and learn more about their gravity-sensing mechanisms.
Science: For IML-2, living matter such as slime mold, Loxodes,
Euglena, jellyfish, Chara, cress roots and lymphocytes will be
examined to determine how gravity affects cells and unicell and
multicell organisms. Also, to investigate the solidification
process of non-living matter at different gravity levels,
scientists will observe a two-component mixture of
succinonitrile-acetone, a transparent material which solidifies
like metal.
Significance: Some plants and animals have specialized cells
or organs that are responsible for perceiving gravity.
Gravity-sensing mechanisms work, along with light and chemical
substances, to keep the living organisms oriented. In order to
provide an ecologically sound environment for extended stays in
space, scientists must know more about the effects of
microgravity on both living and non-living matter.
Experiment Hardware and Operations: The NIZEMI facility
consists of three 19-inch (48 cm) modules. The NIZEMI
Experiment Module contains a support module and the rotating
centrifuge. The support module includes a halogen lamp to
illuminate the samples as they react to the gravity variations,
an electric motor drive for the centrifuge and special locking
devices for the centrifuge during launch and landing. A front
panel of the control unit displays the status of NIZEMI and the
required crew activities. The centrifuge module contains two
observation units, a microscope and a macroscope. The
microscope has magnification powers of 32x, 20x, 10x, 5x and
2.5x. The macrounit has a field of view of 30 mm X 40 mm
(about 1.2 by 1.6 inches) and a depth of focus of approximately
8 mm (0.3 inch). The samples, cameras and stages for moving
and focusing the samples during the experiment are located in
the centrifuge module.
The NIZEMI Control Module has a monitor, recorder,
front panel and the electronics of the video system. The video
system permits display and storage of video signals generated
by the two cameras located on the centrifuge of the experiment
module. These video signals will be merged with display data
from the Experiment Control Unit.
During the mission, the control module will generate
Spacelab closed-circuit television, record and display video
signals, and select the camera signal (macro or micro) to be
transferred to the monitor, recorder or Spacelab.
The experiment control unit has the display,
keyboard, control electronics and power electronics. This
module performs data acquisition for housekeeping and
experiment data, controls the experiment flow and monitors the
status of the NIZEMI facility.
Cuvettes are somewhat akin to slides used with a
conventional microscope, and house samples from each of eight
different experiment types. Once the sample is secured in the
centrifuge module, the crew member will coordinate with the
principal investigator on the ground to make sure the sample
can be observed and recorded during the experiment run.
Temperatures and centrifuge rotation are predetermined and
controlled through the ECU.
Background: The NIZEMI facility will be used for the first
time during IML-2.
Gravisensitivity and Geo(Gravi)taxis of the Slime Mold
Physarum polycephalum (Slime Mold)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Ingrid Block
DLR Institute for Aerospace Medicine
Cologne, Germany
Objective: To add to the understanding of how a single-cell
organism, the slime mold, senses gravity, and to attempt to
locate the specific site at which this perception occurs.
Significance: When the slime mold (Physarum polycephalum) is
on a vertical solid surface it moves downward when surrounded
by air. On the same surface, this same slime mold would move
upward when submerged in water. Scientists do not fully
understand how or why the ectoplasm (elastic wall) of the slime
mold accomplishes rhythmic contractions, although changes in
response to light intensity and gravity have been documented on
previous Space Shuttle flights.
Up to this point, investigators have not been able to
pinpoint the specific site in the slime mold where it can sense
and react to changes in gravity. By observing the behavior of
the slime mold in the NIZEMI facility, scientists hope to be
able to witness changes in the organism as it is subjected to
different levels of gravity.
Operations: This experiment involves observing the single-cell
organism, slime mold, as it is exposed to gravity ranging from
1.5-g to microgravity. After placing a videotape into the
facility's video recording unit, the crew member will remove a
selected slime mold cuvette from the incubator and place it in
the NIZEMI centrifuge. Temperature and lighting are
automatically controlled when the door is closed and locked by
the crew member. Next, the crew member will focus on the
sample slime mold and coordinate with the principal
investigator on the ground. Once the scientist is satisfied
with the location and quality of the sample view, NIZEMI will
automatically process the sample.
Graviorientation in Euglena gracilis (Euglena)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Donat P. H
der
Friedrich-Alexander-University
Erlangen, Germany
Objective: This experiment is intended to determine the lowest
level of gravity which can be sensed by a simple plant organism
called Euglena gracilis. This free-moving single-cell
flagellate orients itself in the water in relation to gravity
and light, to reach the best habitat for photosynthesis and
reproduction.
Scientists hope to learn how the plant's structure
changes in microgravity. Some of the Euglena aboard Columbia
are expected to reproduce, splitting into two organisms. The
principal investigator's team wants to study if these
organisms, which develop entirely in microgravity, react
differently from the cells carried into space. Simple
organisms are easier to study than complex, so scientists
expect to gain insight into Euglena's threshold of sensitivity
to gravity. For example, higher multi-cellular plant life
perceives gravity with an organelle located in the root tip.
The signal has to be transferred to a different part of the
root, which then reacts to gravity's location. In this simple
plant, all three of these activities -- perception,
transduction and reaction, take place within one cell.
Possible experiments for future missions would determine how
the single plant cell transfers and reacts to this information.
Significance: Results based on studies of this unicellular
"primitive" organism are ideal for interpreting and
extrapolating the behavioral responses in more complex
organisms and even humans. Furthermore, these organisms are
ubiquitous and responsible for the production of oxygen. They
also serve as sensitive evaluators for ultraviolet energy and
toxic pollutants, such as heavy metals, which affect the
orientation mechanisms of the cells.
Background: This is the first Shuttle flight for the
experiment, but it has been preceded by extensive work on the
ground. However, one theory suggests that perceiving levels of
gravity is a passive process. It is believed that the back of
the unicellular Euglena is heavier, similar to a buoy in water,
causing the cell to always swim upward.
Other scientists believe that sensing gravity is an
active process where a gravity receptor senses the direction of
the Earth's gravitational field and signals the organism to
swim in the opposite direction. First, Euglena was exposed to
small amounts of ultraviolet radiation which impaired its
ability to sense gravity. Scientists believe if Euglena used
the passive, physical process to sense gravity, it would swim
upwards even when exposed to radiation.
Operations: Team members believe they can determine the
gravity-sensing mechanism by establishing the minimum gravity
level the plant cell can detect and show a reaction to.
The microorganism will be exposed to various levels
of simulated gravity in five-minute- increments in the NIZEMI
slow rotating centrifuge microscope. A sample carried onboard
the Shuttle in a 1-g centrifuge is scheduled to be placed in
the NIZEMI early in the mission. This will be a control sample
to determine Euglena's "normal" threshold of sensitivity to
gravity. The run will start at 0-g, gradually increasing to
1.5-g in five-minute-increments for one hour. Mid-flight, one
sample will be placed in the NIZEMI for an experiment run
starting at 1.5-g and gradually decreasing over one hour to 0-
g. Other experiment runs conducted at the middle and end of
the mission will begin at 0-g, gradually advancing to 1.5-g.
These experiments should enable scientists to assess
how Euglena adapts to microgravity. Video images will be
analyzed with specially designed software, during the mission
and after Columbia lands, to determine precisely when the
micro-organism starts to perceive the simulated gravity and if
the pull of gravity is being sensed by a gravity receptor. A
microscope for observing single cells is mounted on the
centrifuge plate of the NIZEMI apparatus.
Influence of Accelerations on the Spatial Orientation of the
Protozoan Loxodes Striatus (Loxodes)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Ruth Hemmersbach-Krause
DLR Institute for Aerospace Medicine
Cologne, Germany
Objective: This experiment will study the orientation,
velocities and swimming tracks of the unicellular organism,
Loxodes striatus, to determine the threshold levels at which
the organism begins to perceive gravitational forces.
Science: Previous experiments have demonstrated how some
unicell organisms use gravity for their spatial orientation.
One such organism, known as Loxodes striatus, has a specialized
structure, the Mller organelle, which may be responsible for
the perception of gravity. By exposing Loxodes cells to
increasing accelerations in NIZEMI and observing changes in
cell behavior, scientists can better determine the threshold of
gravity perception in these organisms.
Significance: Since these cells may work similarly to the
inner ear of vertebrates, this information is necessary for
scientists to better understand the underlying mechanisms by
which living creatures sense gravity.
Operations: The crew member will load a videotape into the
NIZEMI video recording unit. Next, the crew member will select
a sample of Loxodes cells from the passive thermal conditioning
unit and place it into the facility's centrifuge. When the
door to the centrifuge is closed and locked, temperature and
lighting are automatically controlled. The crew member will
then adjust the microscope to properly focus on the Loxodes,
coordinating with scientists on the ground to ensure the best
available view. NIZEMI automatic operations will then take
over, exposing the Loxodes cells to increasing levels of
acceleration, or artificial gravity, while a magnified view of
the organisms' behavior is provided by the combination
microscope/video camera system.
After landing, the Loxodes cells will be examined at
high magnification by electron microscopy to determine changes
in the structure of the gravity receptor and obtain information
on the biomineralization of single cells.
Effects of Microgravity on Aurelia Ephyra Behavior and
Development (Jellyfish)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Dorothy Spangenberg
Eastern Virginia Medical School
Norfolk, Virginia
Objective: This study of aurelia ephyra,a jellyfish, is
intended to improve scientists' understanding of the effects of
microgravity on the developmental processes of animals and the
role that gravity plays in the developmental responses of
organisms on Earth.
Science: Ten jellyfish will be used inflight during the IML-2
mission. Six Earth-developed ephyrae will be used to study
behavior. Four ephyrae samples will be maintained in a
microgravity environment and the other two will be maintained
at 1-g, or simulated Earth gravity. Two jellyfish in
microgravity will have no gravity-sensing organs (statoliths).
These two will be exposed to different levels of gravity to
determine their gravity threshold for normal behavior. Data
will be obtained post-landing from inflight videotaping of some
of the jellyfish experiments.
The remaining four jellyfish will be flown as polyps
and be exposed to iodine during the flight, causing them to
transform into ephyrae in space. Two of these jellyfish will
be kept in microgravity and two will be centrifuged at 1-g in
the NIZEMI. These jellyfish will be observed at regular
intervals to compare the developmental stages of the ephyrae.
Again, gravity thresholds will be determined by exposing the
jellyfish to different levels of gravity and observing their
behavior. The gravity receptors and muscles of the ephyrae
that develop during flight will be examined after the mission
to determine the presence and nature of any abnormalities.
Significance: This experiment will help scientists better
understand the effects of microgravity on developmental
processes of animals and the role of gravity in the behavioral
and developmental responses of organisms on Earth.
Background: A related experiment flew on the Spacelab Life
Sciences 1 mission in June 1991. Among other things, it
confirmed that, even under microgravity conditions, jellyfish
polyps undergo metamorphosis Q transforming into the free-
swimming ephyrae. However, the behavior of the ephyrae was
modified in microgravity, whether the metamorphosis occurred in
space or on Earth. During space flight, the ephyrae did not
orient themselves as they do on Earth, where they sink mouth-
downward when they stop pulsing. Rather, these ephyrae circled
or looped while swimming and froze when they stopped pulsing.
Operations: After loading a videotape into the facility's
video recording unit, the crew member will remove a cuvette
containing a jellyfish from middeck stowage, place it in a
cuvette holder and install it in the NIZEMI centrifuge. The
crew member will coordinate with the principal investigator
before the centrifuge door is closed and the experiment begins
to run automatically, exposing the jellyfish to varying levels
of microgravity. Some of the jellyfish will be preserved for
post-flight analysis.
Gravireaction in Chara Rhizoids in Microgravity (Chara)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Andreas Sievers
Rheinische Friedrich-Wilhelms-University
Bonn, Germany
Objective: This investigation will use the viewing capability
of the NIZEMI facility to determine the threshold values and
minimal amount of gravitational force necessary for rhizoids of
the simple plant, Chara, to react to gravity and change their
direction of growth.
Science: Chara is a type of green algae that attaches to the
base or material to which a plant is attached and from which it
gets nutrients (substratum) by single cells called rhizoids.
These rhizoids, tube-shaped, root-like organs that grow only at
the tip of the cell, have membrane-enclosed barium sulfate
crystals (statoliths) which cause the rhizoids to shift toward
the force of gravity when the cell is turned or tilted. On
Earth, it has been impossible to determine when the rhizoids
first become sensitive to gravity. Knowledge of rhizoid growth
and structural organization will be combined with video
recordings of microscopic views of statoliths still attached to
the rhizoids.
Significance: This investigation will help scientists
understand how sensitive these single cells are to gravity and
how they adjust to variations in gravity levels. This
experiment, along with the study of cress roots, will add to
scientists' understanding of gravity-sensing mechanisms, which
have been studied intensively on Earth and in space.
Operation: Video microscopy will be used to observe the
behavior of these statoliths in microgravity. The statoliths
will be exposed to microgravity of varying strengths and
durations. A sample of rhizoids will be labeled by the actin-
binding drug phalloidin to allow investigators to observe the
microfilament system where the statoliths are suspended. The
crew member will put a videotape into the NIZEMI facility
recorder before loading a Chara cuvette into the centrifuge.
The crew member will coordinate all adjustments to the
microscope with investigators on the ground. This experiment
will run automatically.
Gravisensitivity of Cress Roots (Cress)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Dieter Volkmann
Rheinische Friedrich-Wilhelms-University
Bonn, Germany
Objective: This experiment will involve exposing chemically
prepared samples of roots from cress plants to varying levels
of gravity, to determine the lowest level at which the roots
become sensitive to changes in gravity.
Significance: If we are to consider raising plants for food
and oxygen in space, we must first understand how changes in
gravity will affect plant growth.
Science: Seedlings of cress must sense gravity in order to
survive. Previous experiments have shown that their roots are
extremely sensitive to even short periods of exposure to
gravity. After the samples have been subjected to
gravitational stimulation in the NIZEMI centrifuge, they will
be examined for indications of any resultant changes. Some of
them will be preserved inflight for postflight examination with
an electron microscope.
Future experiments with cress roots may reveal
whether they can "remember" receiving tiny doses of gravity
that may fall below their normal threshold doses.
Operation: A videotape will be placed in the NIZEMI centrifuge
to capture the data from this experiment. Once this has been
accomplished, the crew member will install a cress root cuvette
and adjust the microscope to provide the best image possible
during processing. This investigation is automatically
controlled through the onboard experiment control unit.
Lymphocyte Movements and Interactions (Motion)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Augusto Cogoli
University of Sassari
Sassari, Italy
Space Biology Group of ETH
Zurich, Switzerland
Objective: This experiment is intended to determine whether or
not T- and B-cells (immune system cells) can contact each
other in a weightless environment.
Science: The activation of T-and B-cells is based on the
exchange of messages, through soluble factors called
lymphokines, as well as through cell-to-cell contact. In this
experiment, colorless, weakly motile cells produced in lymphoid
tissue (lymphocytes) will be observed to determine if they can
make contact in space.
Significance: These cell interactions are critical for many
biological functions, such as antigen recognition by immune
cells. Observing these cells away from the influence of
Earth's gravity will help scientists better understand the
natural workings of the cells. An understanding of how the
immune system works in microgravity will also be important
during extended stays in space.
Operation: These cells will be activated with concavalir-A and
incubated in the 37 degree Celsius (about 98.6 degree
Fahrenheit) Biorack facility. The crew will remove a
lymphocyte cuvette from the incubation rack and place the
sample in the NIZEMI facility. Adjustments to the microscope
will be made and the experiment started. The crew will be
watching the cells' movements and contacts through the
facility's microscope and views of the cells will be downlinked
to scientists on the ground.
Background: This new Biorack experiment, which has not flown
before, uses the NIZEMI facility for observation. A recent
sounding rocket experiment provided direct evidence of cell
contacts, with movements of cells in microgravity being
detected by microscopic observations.
Convection Stability of a Planar Solidification Front (Moni)
Experiment Facility: NIZEMI
Principal Investigator:
Dr. Klaus Leonartz
Aachen Center for Solidification in Space (ACCESS
e.V.)
Aachen, Germany
Objective: This experiment will use the NIZEMI facility to
test a mathematical model for making predictive calculations of
the onset of convection, a type of flow which is caused by
localized density differences in a fluid, such as melted metal.
Science: Convection fluid flow changes the properties of the
melt, as well as the resulting solid. The solidification
process is influenced by gravity, the concentration of the
mixture, temperature levels at which it is heated and cooled
and the speed at which the liquid forms a solid.
Significance: Low-gravity experiments will help improve
materials in the future as scientists begin to understand more
about the solidification process. Many materials are produced
from a melt. Commercially, the most important materials
produced in this manner are metals, and the solidification
process plays a key role in determining the resulting
properties, such as strength and weight.
Operation: For this experiment, a two-component mixture of
succinonitrile-acetone, which is transparent, will be used
because it solidifies like metal. A crew member will place the
cuvette containing the succinonitrile-acetone mixture into the
NIZEMI facility. The transparent quality of this mixture
allows the NIZEMI optical system to be used for observations of
the solidification process as it occurs in low gravity.
Real-Time Radiation Monitoring Device (RRMD)
Payload Developer: NASDA
Principal Investigator:
Dr. Tadayoshi Doke
Waseda University
Tokyo, Japan
Objective: This device will actively measure the high-energy
cosmic radiation which enters the Spacelab in orbit, then
transmit those measurements to the science team at the Payload
Operations Control Center in Huntsville. The signals also will
be transmitted to remote centers where they will be compared
with other current radiation information, such as optical and
X-ray observations.
In addition to real-time radiation monitoring, the
device will contain bacteria with high radiation sensitivity.
Scientists will analyze the bacteria cells post flight to
measure radiation damage and study their ability to recover and
repair themselves after a cosmic-ray impact.
Significance: This IML-2 device is the first to transmit
radiation information to the ground during a mission. It
serves as the beginning toward creation of a space weather-
forecasting network which might be established for future
spacecraft.
Space is a complex environment filled with
electromagnetic radiation and charged particles. Previous
experiments have shown that particles of high-energy radiation
have potentially serious biological effects on living
organisms. Earth's atmosphere shields people on the ground
from most of these effects, but space travelers do not have the
atmosphere to protect them. On longer spaceflights, radiation
storms due to increased levels of solar activity could be
hazardous to astronauts. A reliable space radiation
forecasting system could warn them to take shelter in a
protected area of their spacecraft until the danger has passed.
Experiment Hardware and Operations: The Real-time Radiation
Monitoring Device consists of a detector unit, a control unit,
and passive track dosimeters. The detector rapidly collects
data necessary to analyze the influences of radiation on the
crew, the payload and biological specimens. During the flight,
each time a cosmic ray particle enters the Spacelab, a
spectroscope sensor measures the energy and direction of the
particle. The electronic control unit records signals from the
detector and transmits them to the ground. Also, the
radiation-sensitive bacteria are sandwiched between solid-state
nuclear track detectors in a container on top of the
spectrometer.
The crew will mount the monitoring device in the
Spacelab aft end cone shortly after launch. It will collect
data throughout the mission. Crew members will change the
direction the device faces about once every three days.
After the mission, records of real-time radiation
readings will be compared to information from the passive
radiation trackers, attached with biological specimens on top
of the active detectors. They also will be compared with
Biostack detector data from this and previous missions.
Background: IML-2 is the first flight of this experiment. It
was developed by the National Space Development Agency of Japan
as an addition to their life science hardware from Spacelab-J.
Microgravity Effects on Standardized Cognitive
Performance Measures
Principal Investigator:
Dr. Samuel G. Schiflett
U. S. Air Force Armstrong Laboratory
San Antonio, Texas
Objective: This experiment will help determine astronauts'
mental ability to perform operational tasks in space.
Scientists want to measure how well the crew processes
information so they can distinguish between the effects of
microgravity and fatigue.
Six computerized cognitive performance tests called
the Performance Assessment Workstation (PAWS) will be used
during the flight. After Columbia lands, Air Force personnel,
standing in for the STS-65 crew, will re-enact all mission
procedures. The scientists will compare the results of the two
groups in an effort to precisely pinpoint the effects of
microgravity.
Significance: As technology takes us physically and mentally
farther away from the evolutionary environment of Earth, humans
will be exposed to a variety of conditions that may cause their
performance to deteriorate. The Performance Assessment
Workstation provides scientists with a tool to assess cognitive
performance and, thus, measure the impact of new and unknown
stress factors.
While measurement of performance is only the first
step toward understanding the effects of spaceflight on
cognitive functioning, it also allows space scientists to
quantify any problem so that specific solutions can be
developed to counteract any loss of productivity.
The results will provide information to help planners
more effectively schedule astronauts' work under a variety of
conditions, such as fatigue. This should lead to improved
productivity during space missions through, for example,
scheduling tasks at times when crew members' performance is
optimum.
Science: Present day space travelers are subject to a variety
of stresses during space flight. These include the
microgravity environment, physical isolation, confinement, lack
of privacy, fatigue and changing work-rest cycles. On Earth,
both fatigue and changing work-rest cycles are known to degrade
cognitive performance and productivity.
Hardware: The crew will undergo performance tests using a
laptop computer. The Performance Assessment Workstation tests
are based on current theoretical models of human performance.
They were selected by analyzing tasks involved in space
missions that might be sensitive to microgravity. Subjective
questions also are included in PAWS for interpreting fatigue
and mood states.
The investigation uses a set of six computerized
cognitive performance tests taken from the Unified Tri-Service
Cognitive Performance Assessment Battery. The series of tests
is internationally recognized and has proven sensitive to many
environmental stressors.
Operations: While in orbit, crew members will take the tests
daily. The computer will record the speed and accuracy of the
astronaut's responses to rotated images, letter sequences, math
calculations, spatial patterns and recollection of numbers. It
also records the astronaut's ability to track an unstable
object on the computer screen using a precision trackball.
Perhaps the most challenging test for the astronaut
will be to do two things at one time and rapidly switch
attention between the two tasks. The computer screen will be
divided in half to feature two test questions. Each screen
will be answered in a sequential manner determined by an
indicator at the bottom of the screen. For example, the left
screen might illustrate a spatial ability test while the right
screen features an addition test.
Performance criteria for comparison will be collected
during practice sessions held during the weeks before launch
for the crew member subjects. Also, scientists will continue
to gather data after the astronauts return to Earth. The
postflight data will be collected to determine the rate of
recovery of any detrimental effects of microgravity on
cognitive information processing.
Spinal Changes in Microgravity
Payload Developer: Canadian Space Agency
Principal Investigator:
Dr. John R. Ledsome
Canadian Space Agency
Ottawa, Ontario, Canada
Objective: Two out of every three people who go into space
experience back pain that scientists believe may be related to
a lengthening of the spinal column in microgravity.
The objective of this IML-2 experiment is to
determine whether the lengthening of the spinal column can be
associated with changes in the function of the spinal cord or
spinal nerve roots which branch off the spinal cord. It will
investigate the effects of nerves that are stretched close to
their limits by the lengthened spinal column, as well as the
changes in body function controlled by the central nervous
system.
In addition, the study will determine for the first
time if the lengthening of the spinal column causes changes in
the cardiovascular and bladder functions.
Science: The back does more than allow us to stand up
straight. It houses the spinal cord and nerves that connect
the spinal cord to the other parts of the body. It's likely
that when the nerves are stretched they will not work properly.
This experiment will study two types of these nerves: sensory
nerves that carry signals from the skin to the brain and
autonomic nerves that are responsible for involuntary bodily
functions such as blood flow.
To determine the function of the sensory nerves, the
ability of the spinal cord to conduct an electrical impulse
from the foot to the brain will be measured. Normally when we
breathe in, our heart rate decreases. When the breath is
released, the heart rate increases. If there is a change in
the interaction between breathing and heart rate, it might be
due to changes to the autonomic nerves going to the heart.
The spacing between discs in the vertebrae will be
measured to determine if that is the reason for the height
increase, or if it is due to the straightening of the back's
curvature.
Significance: This experiment will provide an insight into the
function of the major nerves of the spinal cord during space
flight and help understand the back pain reported by
astronauts. The information has already proved valuable in
understanding and assessing chronic back pain on Earth. Some
of the techniques have been applied to back surgery performed
in Canada.
Background: On IML-1, the first systematic measurements of
changes in height and spinal contour were performed. Results
indicated that the astronauts increased in height from two to
three inches. There also was flattening of the normal spinal
contour. Scientists believe this may be the cause of the back
pain that many astronauts experience during space flight.
Operations: The STS-65 crew will complete a daily
questionnaire describing any back pain and associated symptoms
of spinal cord dysfunction, such as numbness. Crew members
also will measure their height daily.
Three times during the flight -- at the beginning,
middle and end -- they will take stereophotographs in seven
different positions designed to provide information about
changes in spinal contour, height and the range of motion of
the vertebral column. They also will be conducted pre- and post
flight, along with magnetic resonance imaging of the spine and
clinical back examination.
To study sensory nerves, crew members will stimulate
their nerves with a tiny electric impulse at the ankle and time
how long it takes the signal to reach the brain using a nerve
stimulation and recording device. On Earth, it usually takes
about 50-thousandths of a second, whereas in space the transit
time is unknown.
To study autonomic nerves, crew members will squeeze
a hand grip measuring device for several minutes -- a form of
isometric exercise. At the same time, blood pressure and heart
rate are measured to determine the adaptation of the heart to
muscular work. A second study will measure heart rate as the
astronaut synchronizes breathing to cues on an audiotape.
Changes in the breathing/heart rate relationships are sensitive
indicators of cardiac changes.
Thermoelectric Incubator (TEI) and
Cell Culture Kits (CCK)
Payload Developer: NASDA
Objective: The Thermoelectric Incubator is a general-purpose
incubator used in the Spacelab module to maintain biological
specimens at a constant temperature, humidity and carbon-
dioxide concentration. It provides a growth environment for
both animal and plant cells.
The Cell Culture Kits will be used to culture slime
mold and plant and animal cells in microgravity. The kits
allow observation of cell growth, the extraction of materials
produced by these cells, and the fixation of the cells for
inspection after return to Earth.
The incubator and cell culture kits also will be used
in conjunction with some of the Free Flow Electrophoresis Unit
experiments.
Significance: This equipment allows scientists in the
microgravity environment of Spacelab to study cell development
and growth in much the same way as they would in their labs on
Earth. Results will provide insight into how microgravity and
radiation affect the development of cells in space. Comparison
with ground-based experiments will help scientists understand
how gravity shapes life on Earth.
Experiment Hardware and Operations: Cell-culture kits are pre-
assembled packages of various items the scientist in orbit
needs to perform culture experiments. They allow astronauts to
take maximum advantage of the time available, as the kits make
available in a single location all the equipment needed for a
particular experiment.
Each kit includes a main chamber, containers for
culture mediums, waste collectors, applicators, syringes and
containment bags. For IML-2, three different types of kits
will support animal cell-culture and electrophoresis
experiments. Petri-dish-type chambers will be used for the
slime mold and plant cells. Animal cell culture kits have
transparent windows which allow crew members to observe cell
cultures grown in orbit with a Biological Microscope. They
will use a 35-mm camera, which attaches to the microscopes, to
make still photographs of the samples.
For the slime mold culture, a video system will
record and downlink real-time images of specimens to scientists
at Spacelab Mission Operations Control in Huntsville.
The Thermoelectric Incubator will operate at around
98.6 degrees Fahrenheit (37 degrees C). Experiment samples
within the incubator are secured by a bungee cord to prevent
damage from vibration and keep them from floating away when the
door is opened.
Background: This equipment is provided by the National Space
Development Agency of Japan. Along with the Free Flow
Electrophoresis Unit and the Aquatic Animal Experiment Unit, it
was part of the First Material Processing Test P Life Sciences,
which flew aboard the Spacelab-J mission in 1992.
Gravity and the Stability of the
Differentiated State of Plant Embryos
Experiment Facility: Cell Culture Kits
Principal Investigator:
Dr. Abraham Krikorian
State University of New York at Stony Brook
Stony Brook, New York
Objective: This experiment aims at determining the role
gravity plays in the earliest stages of plant development. It
will grow daylily and carrot cells in two different culture
environments to validate the outcome of its predecessor
experiment on Spacelab-J. On that mission, a large number of
plant cells developed with two nuclei. Cell division was
taking place, but the walls which should have separated the two
cells did not form.
Significance: This experiment will help determine if cell
development can begin in the absence of gravity. It tests and
profiles critical stages in plant cell development, called
embryogenesis, and examines the effect of microgravity on cell
division and chromosome behavior. The experiment also tests
for other space environment effects such as radiation.
Results will provide fundamental biology information
about the workings of a cell on Earth. Potential long-term
benefits could range from manufacture of artificial seeds to
the storage of vast, varied food supplies in a very small space
(the size of a culture dish). This knowledge is critical for
implementing space-based plant biotechnologies to feed future
space travelers on long planetary flights.
Operations: Carrot and daylily cells will be grown in six
plant cell chambers and six plant fixation chambers, so that
two basic types of cell culture environments can be evaluated.
Astronauts will place a radiation detector with the
plant cell chambers and store them in a Spacelab rack
compartment when the experiment begins. Cells with the ability
to develop into embryos will be launched in a culture medium
which keeps them inactive. Within a few days, the cells will
be automatically developed themself. These samples will be
stored in the rack as well. Late in the flight, the crew will
add a chemical to some of the cells to stop their growth and
preserve their characteristics.
Comparison of the preserved samples with those
returned to Earth alive will ensure that any abnormalities seen
in the cells are not due to the stress of landing. Some of the
space flight embryos will be incubated after the flight and
examined on an ongoing basis for any temporary or longer-term
effects of their genesis in the absence of gravity.
Background: On Dr. Krikorian's Spacelab-J experiment, both the
degree and rate of development of plant cell generation were
altered. There were significant abnormalities in the status
and behavior of the nucleus of cells making up the embryo, with
fracturing and changes in chromosome structure.
Effects of Microgravity on the Growth and
Differentiation of Cultured Bone-Derived Cells
Experiment Facility: TEI
Principal Investigator:
Dr. Yasuhiro Kumei
Tokyo Medical and Dental University
Tokyo, Japan
Objective: This experiment compares functional differences in
bone cell cultured in Earth's gravity compared to cells
cultured in microgravity and determines the genes responsible
for any differences. The ultimate goal is to clarify the
causes for the bone atrophy, or osteoporosis, induced by space
flight.
Significance: Previous Shuttle experiments have shown that
animals lose calcium during space flight. Ninety percent of
the calcium is found in the bone. Bone loss could pose more
serious hazards for space travelers on long-duration missions.
It's hypothesized that genes governing bone production are
either stimulated or suppressed during space flight.
In addition to benefiting the health of future space
crews, an increased understanding of the mechanism of
osteoporosis eventually could help prevent bone disease on
Earth and improve therapy for immobilized patients who
experience similar bone atrophy.
Operations: Four culture chambers filled with bone cells from
the back legs of young adult rodents will be studied in this
experiment. Those cells are particularly sensitive to the
sudden absence of gravity's pull on the skeleton in space.
Astronauts will make microscopic and photographic observations
of cell growth through transparent windows in the animal cell
culture containers.
The cultures will grow in the Thermoelectric
Incubator at 98.6 degrees Fahrenheit (37 degrees C), beginning
just a few hours after launch. Three days later, crew members
will remove two culture chambers from the incubator. They will
extract cell samples from both chambers and refrigerate them.
Other samples from those two containers will be frozen. The
two remaining cell culture containers will continue to incubate
until Flight Day 9, when the collection procedure will be
repeated.
After the mission, the samples will be examined for
the differences in bone cell production during exposure to
microgravity.
Differentiation of Dictyostelium discoideum in Space
Experiment Facility: Cell Culture Kits
Principal Investigator:
Dr. Takeo Ohnishi
Nara Medical University
Nara, Japan
Objective: This experiment will provide information on how
microgravity and radiation stress cells in space and affect
their genetic development and shape. Two strains of slime mold
cells (Dictyostelium discoideum), whose distinctive development
has been studied extensively on Earth, will be grown in space
to identify any differences.
Significance: Slime molds, found among decaying forest leaves
and in topsoil, emerge from spores. During cell
differentiation, (the process through which the molds attain
their adult form) the spores show very distinct structural
changes at various stages of cell division. Scientists are
quite familiar with these structural stages on Earth, so
comparisons with cells grown in orbit should provide extensive
insight into how cell development and differentiation are
affected by the space environment.
Operations: This experiment will grow a radiation-sensitive
strain of slime mold and a wild-type strain which should be
capable of DNA repair against radiation damage. Comparison of
the two strains' development will help distinguish between the
effects of microgravity and those of cosmic rays.
The organisms will be grown in plant cell culture
chambers. Shortly after the IML-2 payload is activated, a crew
member will remove the slime mold cell culture kit from its
middeck locker. After attaching a radiation detector to the
kit, the astronaut will place it in the middeck
refrigerator/incubator.
On Flight Day 2, an astronaut will remove the slime
mold kit from the refrigerator, incubate it for an hour in the
Biorack incubator, then activate growth by injecting a buffer
solution into the culture. The kit will be put back in the
Biorack incubator, where it will remain for 4-1/2 days at 72
degrees Fahrenheit (22 degrees C). A video camera attached to
the culture chamber will observe and record changes in cell
shapes during growth. As they are taken, the images will be
downlinked to experiment controllers on the ground.
After the flight, scientists will evaluate the health
of the spores grown in space. Radiation effects will be
determined by comparing the two types of slime mold.
ORBITAL ACCELERATION RESEARCH EXPERIMENT (OARE)
Payload Developer: NASA
Project Manager:
Mr. Jose L. Christian, Jr.
NASA Lewis Research Center
Cleveland, Ohio
Objective: There is no hard boundary between Earth's
atmosphere and space, no line where one ends and the other
begins. The planet's atmosphere is thickest at the surface and
thins gradually with increasing elevation. Even the altitudes
reached by the Space Shuttle are not completely devoid of air.
The Shuttle travels very rapidly through this tenuous
atmosphere (near vacuum), and is slightly slowed (decelerated)
by friction with it. Because the density of the atmosphere
changes from day to night, the amount of friction (decelerating
force) varies proportionally.
The Orbital Acceleration Research Experiment (OARE)
makes extremely accurate measurements of these variations and
other disturbances with a sensor called an accelerometer and
records them for later analysis. By analyzing these and other
types of microgravity disturbances, researchers can assess the
influence of Shuttle accelerations on scientific experiments
carried onboard.
Significance: The OARE is an instrument that monitors and
records extremely small accelerations (changes in velocity) and
vibrations experienced during Space Shuttle on-orbit
operations. The OARE has already flown successfully on a
number of Space Shuttle missions as part of the Orbiter
Experiment Program (OEX). These previous missions had two
objectives: to provide scientists with important information
regarding aerodynamic drag (friction with the atmosphere) and
upper atmosphere density (thickness of the air at high
altitudes) that is impossible to obtain on Earth, and to study
the high velocity, low density flight environment known as
rarefied flow aerodynamics. This basic research has helped
scientists better understand the upper atmosphere and
aerodynamic behavior in it.
The OARE hardware is being pressed into service once
again, this time to augment the ongoing study of the Space
Shuttle's acceleration environment. The OARE will extend
measurements currently being provided by the Space Acceleration
Measurement System (SAMS). The OARE is capable of sensing and
recording accelerations on the order of one billionth the
acceleration of Earth's gravity (1 nano-g) at a rate of change
(frequency) of less than once per second (1 Hz). These
measurements will provide a more complete picture of the
microgravity (low gravity) environment in the Space Shuttle.
Scientists will use this information to determine how the
disturbances influence experiment behavior.
Experiment Hardware and Operations: At the heart of the OARE
system is the Miniature Electrostatic Accelerometer (MESA).
The MESA has a cylindrical mass (called a proof mass) suspended
within the accelerometer housing. The proof mass is pulled in
different directions by static electric fields applied to
electrodes within the housing. When the fields exert an equal
pull in all directions on the proof mass, it floats between
them. This is known as electrostatic suspension. An
acceleration in any direction will cause the proof mass to move
with respect to its enclosure, distorting the suspending
electrostatic field. These field distortions are proportional
to the applied acceleration and are measured and interpreted by
OARE's electronics.
The accelerometer mounts on a movable table that
allows accurate alignment with respect to the Shuttle's flight
direction. In-flight calibration is also made possible by the
movable mounting system. During calibration of the
accelerometer, any inherent accelerometer error is determined
and can be compensated for in post-flight data analysis. The
OARE's nano-g sensitivity makes it impossible to calibrate on
Earth, since there is no place quiet (vibration free) enough at
this level of acceleration.
Once activated, the OARE operates autonomously and
follows a pre-programmed sequence of operation modes. For
example, calibration is normally performed at regular,
predetermined intervals, but a sensor saturation (an
acceleration greater than the sensor is designed to measure)
will trigger an automatic initialization and calibration. the
OARE software conditions the acceleration data by removing
frequencies above 1 Hz, and records the data on magnetic tape.
The instrument is provided by NASA's Lewis Research
Center in Cleveland, Ohio.
Commercial Protein Crystal Growth
This payload is sponsored by the Office of Advanced
Concepts and Technology (OACT) as part of the commercial
development of space programs within the OACT Space Processing
Division. The payload and payload management are with the
Center for Macromolecular Crystallography located at the
University of Alabama at Birmingham, a NASA Center for the
Commercial Development of Space.
This is the fifth flight (CPCG-05) of the protein
crystal growth secondary payloads using the Commercial
Refrigerator/Incubator Module (CRIM) in the Shuttle middeck.
This complement of experiments contains 60 different samples
focusing on six proteins in various formulations to enhance the
probabilities for successful results. The crystals will be
grown using the CMC Vapor Diffusion Apparatus (VDA) which
allows proteins to be processed at a temperature of four
degrees C rather than the normal 22 degrees C. The lower
temperature requires a longer processing time which will be
satisfied by the STS-65 14-day mission duration.
Commercial partners on this experiment with the UA-B
CMC are SmithKline Beecham Pharmaceuticals and Vertex
Pharmaceuticals. The firms and the university are researching
the development of drugs which could provide some benefit to
victims of AIDS, osteoporosis and toxic shock syndrome as well
as providing a better understanding of the regulation of the
human immune system and antibiotic resistance.
Dr. Larry DeLucas is the Director of the Center for
Macromolecular Crystallography. The UA-B protein crystal
growth apparatus first flew on STS-26 in September 1988, and in
various improved versions, has flown 16 previous missions, the
most recent of which was STS-62 in March.
AIR FORCE MAUI OPTICAL SYSTEM
The Air Force Maui Optical System (AMOS) is an
electrical-optical facility on the Hawaiian Island of Maui. No
hardware is required aboard Columbia to support the
experimental observations. The AMOS facility tracks the orbiter
as it flies over the area and records signatures from thruster
firings, water dumps or the phenomena of "Shuttle glow," a
well-documented fluorescent effect created as the Shuttle
interacts with atomic oxygen in Earth orbit. The information
obtained by AMOS is used to calibrate the infrared and optical
sensors at the facility. AMOS is a Department of Defense
payload and is flown under the direction of the DOD Space Test
Program.
MILITARY APPLICATIONS OF SHIP TRACKS
The Office of Naval Research (ONR) is sponsoring the
Military Applications of Ship Tracks (MAST) experiment on STS-
65. MAST is part of a five-year research program developed by
ONR to examine the effects of ships on the marine environment.
The Naval Postgraduate School, Monterey, Calif., will conduct
the experiment at JSC during the mission. The objective of
MAST is to determine how pollutants generated by ships modify
the reflective properties of clouds. Ship tracks are observed
in satellite imagery as long, narrow, curvilinear cloud
features that have greater brightness than the surrounding
clouds. The STS-65 crew will photograph ship tracks using
handheld cameras. These high-resolution photographs will
provide insight into the processes of ship track production on
a global scale. MAST will help in understanding the effects of
man-made aerosols on clouds and the resulting impact on the
climate system. MAST is a Department of Defense payload and is
being flown under the direction of the DOD Space Test Program.
Shuttle Amateur Radio EXperiment (SAREX)
Students in the U.S., Germany and Japan will have a
chance to speak, via amateur radio, with astronauts aboard the
Space Shuttle Columbia during STS-65. Ground-based amateur
radio operators ("hams") will be able to contact the Shuttle
through automated computer-to-computer amateur (packet) radio
links. There also will be voice contacts with the general ham
community as time permits.
Shuttle mission specialists Donald A. Thomas (call
sign KC5FVF) and Robert D. Cabana (license pending) will talk
with students in 13 schools in the U.S., Germany and Japan
using "ham radio."
Students in the following schools will have the
opportunity to talk directly with orbiting astronauts for
approximately 4 to 8 minutes:
* Sacred Hearts Academy, Honolulu, HI (WH6CJU)
* Kline School, Costa Mesa, Calif. (WB6NUD)
* Mountain View School, Phoenix, AZ (WB7VVD)
* Granite Mountain Middle School, Prescott, AZ (KB7TRE)
* West Monroe High School, West Monroe, LA (N5MYH)
* Our Lady Queen of Heaven, Lake Charles, LA (N5JDB)
* Richland Elementary, Ft. Worth, TX (KB5CXR)
* West-Oak High School, Westminster, SC (KR5GZ)
* Brentwood School, Sanderville, GA (AD4ID)
* Bair Middle School, Sunrise, FL (W4ROA)
* South Seminole Middle School, Casselberry, FL (KD4SRD)
* Fronhofer-Realschule Ingolstadt, Bavaria, Germany (DG4MKR)
* Tatebayashi Children's Science Exploratorium, Gunma, Japan
(JQ1GOE)
The radio contacts are part of the SAREX (Shuttle
Amateur Radio EXperiment) project, a joint effort by NASA, the
American Radio Relay League (ARRL), and the Radio Amateur
Satellite Corporation (AMSAT).
The project, which has flown on 13 previous Shuttle
missions, is designed to encourage public participation in the
space program and support the conduct of educational
initiatives through a program to demonstrate the effectiveness
of communications between the Shuttle and low-cost ground
stations using amateur radio voice and digital techniques.
Information about orbital elements, contact times,
frequencies and crew operating schedules will be available
during the mission from NASA, ARRL (Steve Mansfield, 203/666-
1541) and AMSAT (Frank Bauer, 301/ 286-8496). AMSAT will
provide information bulletins for interested parties on
INTERNET and amateur packet radio. The ARRL bulletin board
system (BBS) number is (203) 688-0578.
The ARRL ham radio station (W1AW) will include SAREX
information in its regular voice and teletype bulletins.
Mission information will be available online from the
Johnson Space Center computer bulletin board (8 N 1 1200 baud):
dial (713) 244-5625. BBS information is available from the
Goddard Space Flight Center amateur radio club via Internet.
The address is: wa3nan.gsfc.nasa.gov.
The amateur radio station at the Goddard Space Flight
Center, (WA3NAN), will operate around the clock during the
mission, providing SAREX information, retransmitting live
Shuttle air-to-ground audio, and retransmitting many SAREX
school group contacts.
STS-65 SAREX Frequencies
Routine SAREX transmissions from the Space Shuttle
may be monitored on a worldwide downlink frequency of 145.55
MHz.
The voice uplink frequencies are (except Europe):
144.91 MHz
144.93
144.95
144.97
144.99
The voice uplink frequencies for Europe only are:
144.70
144.75
144.80
Note: The astronauts will not favor any one of the above
frequencies. Therefore, the ability to talk with an astronaut
depends on selecting one of the above frequencies chosen by the
astronaut.
The worldwide amateur packet frequencies are:
Packet downlink 145.55 MHz
Packet uplink 144.49 MHz
The Goddard Space Flight Center amateur radio club
planned HF operating frequencies:
3.860 MHz
7.185 MHz
14.295
21.395
28.650
STS-65 CREW BIOGRAPHIES
Robert D. Cabana, 45, Col., USMC, will be Commander
(CDR) of STS-65. Selected as an astronaut in 1985, Cabana was
born in Minneapolis, Minn., and will be making his third space
flight.
Cabana graduated from Washburn High School,
Minneapolis, in 1967 and received a bachelor's degree in
mathematics from the Naval Academy in 1971.
Cabana completed naval flight officer training in
1972 and then served as an A-6 bombardier/navigator with Marine
Air Wings, Cherry Point, N.C., and Iwakuni, Japan, until 1975.
He then completed pilot training and was designated a naval
aviator in 1976, and assigned to Cherry Point where he flew A-6
Intruders. In 1981, he graduated from the Naval Test Pilot
School and later served at the Naval Air Test Center as the A-6
program manager, X-29 advanced technology demonstrator project
officer, and as a test pilot for flight systems and ordnance
separation testing on the A-6 and A-4 aircraft. At the time of
his selection by NASA, he was serving as the assistant
operations officer of Marine Aircraft Group Twelve in Iwakuni.
Cabana's first Shuttle flight was as pilot of STS-41
in October 1990, a mission that deployed the Ulysses planetary
probe to study the polar regions of the Sun. He next flew as
pilot of STS-53 in December 1992, a mission that deployed the
classified Department of Defense-1 payload.
Cabana has logged more than 273 hours in space and
more than 4,700 flying hours in 32 different types of aircraft.
James Donald Halsell, Jr., 37, Lt. Col., USAF, will
serve as Pilot of STS-65.
Selected as an astronaut in 1990, Halsell was born in
Monroe, La., and will be making his first space flight.
Halsell graduated from West Monroe High School in
1974; received a bachelor's degree in engineering from the Air
Force Academy in 1978; received a master's degree in management
from Troy University in 1983; and received a master's degree in
space operations from the Air Force Institute of Technology in
1985.
Halsell completed undergraduate pilot training at
Columbus Air Force Base, Mississippi, in 1979 and was assigned
to Nellis Air Force Base, Las Vegas, Nev., as an F-4D aircraft
commander. In 1981, he was stationed at Moody Air Force Base,
Valdosta, Ga., serving as squadron flight lead, instructor
pilot, strike package commander and chief of the Squadron
Standardization/Evaluation Branch. Later, as a student at the
Air Force Institute of Technology, Wright-Patterson Air Force
Base, Dayton, Oh., his master's thesis prototyped a space
rescue transfer vehicle using off-the-shelf equipment and was
sponsored by the Johnson Space Center's (JSC) Crew Systems
Division. Halsell then attended the Air Force Test Pilot
School at Edwards Air Force Base, Calif., serving as a test
pilot in the F-4, F-16 and the SR-71 aircraft in the years
following his graduation.
Richard J. Hieb, 38, will be Payload Commander and
Mission Specialist 1 (MS1). Selected as an astronaut in 1985,
Hieb was born in Jamestown, N.D., and will be making his third
space flight.
Hieb graduated from Jamestown High School in 1973;
received a bachelor's degree in math and physics from Northwest
Nazarene College in 1977; and received a master's degree in
aerospace engineering from the University of Colorado in 1979.
Hieb joined NASA in 1979, working at JSC in crew
procedures development and crew activity planning. He worked
on the ascent team in Mission Control for STS-1 and during
rendezvous phases of many subsequent missions, specializing in
rendezvous and proximity operations.
He first flew as a Mission Specialist on STS-39 in
May 1991, a Department of Defense mission that deployed and
later retrieved the Infrared Background Signature Survey
satellite. His next flight was as a Mission Specialist on STS-
49 in May 1992, a mission that retrieved and repaired the
stranded Intelsat VI F3 communications satellite. During that
flight, Hieb performed three space walks totaling more than 17
hours for the capture and repair of the satellite.
Hieb has logged more than 400 hours in space.
Carl E. Walz, 38, Lt. Col., USAF, will be Mission
Specialist 2 (MS2). Selected as an astronaut in 1990, Walz was
born in Cleveland, Oh., and will be making his second space
flight.
Walz graduated from Charles F. Brush High School,
Lyndhurst, Oh., in 1973; received a bachelor's degree in
physics from Kent State University in 1977; and received a
master's degree in solid state physics from John Carroll
University in 1979.
Walz was commissioned in the Air Force following
graduation from Kent State, and after completing graduate
studies at John Carroll, he was assigned to the 1155th
Technical Operations Squadron at McClellan Air Force Base,
Calif. In 1983, he attended the Air Force Test Pilot School at
Edwards Air Force Base, Calif., as a flight test engineer, and
he was assigned to the F-16 Combined Test Force at Edwards
following graduation.
Walz' first Shuttle flight was as a Mission
Specialist on STS-51 in September 1993, a mission that deployed
the Advanced Communications Technology Satellite. Walz has
logged more than 236 hours in space.
Leroy Chiao, Ph.D., 33, will be Mission Specialist 3
(MS3). Selected as an astronaut in 1990, Chiao considers
Danville, Calif., his hometown and will be making his first
space flight.
Chiao graduated from Monte Vista High School in
Danville in 1978; received a bachelor's degree in chemical
engineering from the University of California, Berkeley, in
1983; and received a master's degree and a doctorate in
chemical engineering from the University of California, Santa
Barbara, in 1985 and 1987, respectively.
In 1987, Chiao joined the Hexcel Corporation in
Dublin, Calif., working in process, manufacturing and
engineering research on advanced aerospace materials. Chiao
joined the Lawrence Livermore National Laboratory in 1989 and
performed processing research on filament-wound and thick-
section aerospace composites. Chiao developed and demonstrated
a mechanistic cure model for graphite fiber/epoxy composite
material.
Chiao's technical assignments as an astronaut have
included Shuttle flight software verification and work with
crew equipment design issues.
Donald A. Thomas, Ph.D., 39, will be Mission
Specialist 4 (MS4). Selected as an astronaut in 1990, Thomas
was born in Cleveland, Oh., and will be making his first space
flight.
Thomas graduated from Cleveland Heights High School
in 1973; received a bachelor's degree in physics from Case
Western Reserve University in 1977; and received a master's
degree and a doctorate in materials science from Cornell
University in 1980 and 1982, respectively.
Thomas joined AT&T Bell Laboratories in 1982 as a
senior member of the technical staff, working on high density
interconnections of semiconductor devices. He also served as
an adjunct professor in the Trenton State College Physics
Department.
In 1987, he joined Lockheed Engineering and Sciences
Company in Houston where his work involved reviewing materials
for Shuttle payloads. He joined NASA in 1988 as a materials
engineer at JSC, performing work that involved lifetime
projections of advanced composite materials for use on space
station. He also was a principal investigator for the
Microgravity Disturbances Experiment, a crystal growth
experiment which flew on STS-32 in January 1990.
Thomas' technical assignments in the Astronaut Office
have included working as a spacecraft communicator in Mission
Control and as a representative to the safety and operations
development branches.
Chiaki Naito-Mukai, M.D., Ph.D., 41, will be Payload
Specialist 1 (PSI).
Selected as a science astronaut by the National Space
Development Agency of Japan (NASDA) in 1985, Mukai was born in
Tatebayashi, Gumma Prefecture, Japan, and will be making her
first space flight.
Mukai graduated from Keio Girls' High School, Tokyo,
in 1971; received her doctor of medicine degree from Keio
University School of Medicine in 1977; and received a doctorate
in physiology from the Keio University School of Medicine in
1988. She was board certified as a cardiovascular surgeon by
the Japan Surgical Society in 1989.
Mukai was board certified for Clinical Medicine in
1977, and, until 1979, worked as a resident in General Surgery
at Keio University Hospital, Tokyo. In 1978, she was on the
medical staff in Emergency Surgery at Saiseikai Kanagawa
Hospital, Kangewa Prefecture. In 1980, she began work as a
resident in cardiovascular surgery at Keio University Hospital
and on the medical staff of cardiovascular surgery at Saisekai
Utsunomiya Hospital, Tochigi Prefecture. In 1983, she returned
to Keio University Hospital as the chief resident in
cardiovascular surgery and later became the assistant professor
of the Department of Cardiovascular Surgery.
Mukai was selected by NASDA in 1985 as one of three
payload specialist candidates for the Japanese Spacelab,
Spacelab-J, on Shuttle mission STS-47. She became a visiting
scientist of the Division of Cardiovascular Physiology at the
Space Biomedical Research Institute at JSC from 1987 to 1988.
Mukai is credited with more than 50 publications since 1979.
STATISTICAL STUDY OF SPACE SHUTTLE PRODUCTIVITY
(Through STS-59 landing, April 20, 1994)
SIGNIFICANT MILESTONES
Missions Launched: 61 (approx. 6 percent of total U.S.
launches)
Mission Success Rate: 98.387 percent (61 of 62 flights
successful)
Miles Traveled: Over 134 million statute miles
Orbits Flown: Over 6,380
HUMAN ACTIVITY ON SHUTTLE
Shuttle Man-Years in Orbit: 5.9 (65 percent of total U.S. man-
years)
(25 percent of total man-years)
Individuals Flown in Space on Shuttle: 162 (55 percent of
total humans in
space)
* 146 U.S. flyers (80 percent of total Americans in space)
* 16 non-U.S. flyers representing 10 countries
* 89 flyers have made multiple flights
SHUTTLE PAYLOADS LAUNCHED & RETURNED
Payloads to Orbit: 671 (approx. 56 percent of total U.S.
payloads to orbit)
(approx. 16 percent of total announced payloads to orbit)
(Note: Includes major attached payloads and experiments,
deployables)
Payloads Returned to Earth: 637
Satellites Deployed: 51
Satellites Retrieved and Repaired: 3 (Solar Max, LEASAT-3,
INTELSAT-V)
Satellites Retrieved and Returned to Earth: 9 (2 refurbished
and relaunched)
SHUTTLE WEIGHT-LIFTING RECORD
Cargo Weight to Orbit: 1.67 million lbs (837 tons) (45 percent
total U.S.)
Cargo Weight Deployed: 756,000 lbs (378 tons)
Total Weight (including Orbiters) to Orbit: approx. 13.7
million lbs
MISCELLANEOUS
Shuttle Rendezvous Operations: 16
Shuttle Spacewalks (EVAs): 20 (16 planned and 4 unplanned; 6
free-flyers)
Total Shuttle EVA Time: 223 hours
Space-walking Shuttle Astronauts: 22 (46 percent of total U.S.
spacewalkers)
Women Flown in Space on Shuttle: 19
American Minority Astronauts Flown: 11
Members of Congress Flown: 2
Shuttle Orbiter Flights
Discovery 18
Columbia 16
Atlantis 12
Challenger 10
Endeavour 6
Spacelab Missions: 13 (including 106 days, 18 hrs. of science
operations)
Note: These statistics are based on announced information and
as such, are somewhat conservative. Some information regarding
Department of Defense missions was unavailable for these
calculations.
IML-2 MODULE RACK (graphic)
PREVIOUS SHUTTLE MISSIONS (graphic)